Hybrid finite-amplitude periodic modes for two uniformly magnetized spheres.

We analyze a system of two uniformly magnetized spheres, one fixed and the other free to slide in frictionless contact with the surface of the first. The centers of the two magnets, and their magnetic moments, are restricted to a plane. We search for sets of initial conditions that yield finite-amplitude oscillatory periodic solutions. We extend two small-amplitude base modes, one with orbital and spin motions that are in phase and the other out of phase, to finite amplitudes and show that the motion for arbitrary oscillatory solutions can be considered to be a nonlinear superposition of these base modes. Some solutions are pure periodic finite-amplitude extensions of one base mode, while others are hybrid finite-amplitude superpositions of the two modes. Hybrid modes with rational frequency ratios are periodic and come in families defined by their frequency ratios. We further characterize hybrid periodic modes by identifying two symmetry classes that describe their relative phases. We see continuous transitions between one finite-amplitude base mode and the other, with one mode gradually transforming into the other. We also calculate frequency spectra of nonperiodic modes, show that the two base modes have well-defined frequencies even for nonperiodic states, and show that periodic solutions can give clues about the behavior of nearby nonperiodic solutions. In the limit of small amplitudes, we confirm that the computed frequencies of these modes agree with small-amplitude analytical results. We also generate a Lyapunov exponent heatmap that reflects periodic and nonperiodic regions of state space.

Conducting qualitative research through time: how might theory be useful in longitudinal qualitative research?

This paper explores the use of theory in longitudinal qualitative research, an approach to research which explores lived experiences as they unfold. The authors illustrate how the complexity of conducting qualitative research through time drives an understanding and use of theory that differs from other research approaches. Longitudinal qualitative research considers time as fluid, subjective, and unbounded-in contrast to the more common taken-for-granted understanding of time as fixed, objective, and linear. Furthermore, longitudinal qualitative research is predicated on a premise of trust in the context of enduring research relationships. Therefore, while subject-matter theories used to investigate topics of interest to health professions educators may be useful frameworks for other types of research, longitudinal qualitative research needs theories that accommodate the myriad of changes in lived experiences through time. The authors share their decade-long, longitudinal qualitative research story, highlighting their decision points and insights. In doing so, they foreground issues such as time as fluid as an important contribution to health professions education literature.

Inertial motion on the earth's spheroidal surface.

As seen by an observer in the rotating frame, the earth's small spheroidal deformations neutralize the centrifugal force, leaving only the smaller Coriolis force to govern the "inertial" motion of objects that move on its surface, assumed smooth and frictionless. Previous studies of inertial motion employ weakly spheroidal equations of motion that ignore the influence of the centrifugal force and yet treat the earth as a sphere. The latitude dependence of these equations renders them strongly nonlinear. We derive and justify these equations and use them to identify, classify, name, describe, and illustrate all possible classes of inertial motion, including a new class of motion called circumpolar waves, which encircle both poles during each cycle of the motion. We illustrate these classes using CorioVis, our freely available Coriolis visualization software. We identify a rotational/time-reversal symmetry for motion on the earth's surface and use this symmetry to develop and validate closed-form small-amplitude approximations for the four main classes and one degenerate class of inertial motion. For these five classes, we supply calculations of experimentally relevant frequencies, zonal drifts, and latitude ranges.

Normal-mode oscillations for the circular and dipolar states of a filled hexagonal magnetic dipole cluster.

We analyze the rotational dynamics of six magnetic dipoles of identical strength at the vertices of a regular hexagon with a variable-strength dipole in the center. The seven dipoles spin freely about fixed axes that are perpendicular to the plane of the hexagon, with their dipole moments directed parallel to the plane. Equilibrium dipole orientations are calculated as a function of the relative strength of the central dipole. Small-amplitude perturbations about these equilibrium states are calculated in the absence of friction and are compared with analytical results in the limit of zero and infinite central dipole strength. Normal modes and frequencies are presented. Bifurcations are seen at two critical values of the central dipole strength, with bistability between these values.

Periodic bouncing modes for two uniformly magnetized spheres. II. Scaling.

A uniformly magnetized sphere moves without friction in a plane in response to the field of a second, identical, fixed sphere and makes elastic hard-sphere collisions with this sphere. Numerical simulations of the threshold energies and periods of periodic finite-amplitude nonlinear bouncing modes agree with small-amplitude closed-form mathematical results, which are used to identify scaling parameters that govern the entire amplitude range, including power-law scaling at large amplitudes. Scaling parameters are combinations of the bouncing number, the rocking number, the phase, and numerical factors. Discontinuities in the scaling functions are found when viewing the threshold energy and period as separate functions of the scaling parameters, for which large-amplitude scaling exponents are obtained from fits to the data. These discontinuities disappear when the threshold energy is viewed as a function of the threshold period, for which the large-amplitude scaling exponent is obtained analytically and for which scaling applies to both in-phase and out-of-phase modes.

Periodic bouncing modes for two uniformly magnetized spheres. I. Trajectories.

We consider a uniformly magnetized sphere that moves without friction in a plane in response to the field of a second, identical, fixed sphere, making elastic hard-sphere collisions with this sphere. We seek periodic solutions to the associated nonlinear equations of motion. We find closed-form mathematical solutions for small-amplitude modes and use these to characterize and validate our large-amplitude modes, which we find numerically. Our Runge-Kutta integration approach allows us to find 1243 distinct periodic modes with the free sphere located initially at its stable equilibrium position. Each of these modes bifurcates from the finite-amplitude radial bouncing mode with infinitesimal-amplitude angular motion and supports a family of states with increasing amounts of angular motion. These states offer a rich variety of behaviors and beautiful, symmetric trajectories, including states with up to 157 collisions and 580 angular oscillations per period.

Discovering the Benefits of Group Peer Review of Submitted Manuscripts.

Problem: Traditionally, journal editors expect individuals to complete peer reviews of submitted manuscripts on their own. Recently, a number of editors of health sciences journals have begun to support, and even espouse, the practice of group peer review (GPR). With GPR, multiple individuals work together to complete the review with permission from the journal editor. Motivated by the idea that GPR could provide a meaningful service learning experience for participants in an interprofessional educational scholarship course, we conducted three such reviews and subsequently reflected on our experience and the lessons we learned. We frame our reflections using guiding principles from the domains of peer review, professional development, and educational scholarship. Intervention: The course director arranged for manuscripts to review with the editors of three health sciences journals. Each GPR occurred during a separate weekly session of the course. Each GPR was completed using a similar set of steps, which included (a) gaining familiarity with review criteria, (b) reading aloud and discussing the manuscript's abstract as a class, (c) reading and critiquing assigned sections as individuals and then small groups, (d) building consensus and sharing notes, (e) having the course director synthesize notes into a single review for submission to the journal. Context: The course on educational scholarship involved 15 faculty representing faculty from the University of Utah's School of Medicine, College of Nursing, College of Pharmacy, College of Health, and School of Dentistry. The course director led three GPR sessions mid-way through the yearlong course. Impact: Participants' reflections indicate that GPR (a) conformed to principles of effective peer review; (b) resulted in a meaningful service learning experience within a formal professional development program, deepening understanding of core concepts of educational scholarship; and (c) represented an authentic example of engaging in educational scholarship (i.e., designing and evaluating an intervention while drawing upon and contributing to a body of shared understanding within a community of practice). Lessons Learned: Our principles-based approach to completing GPR within a professional development course on educational scholarship can serve as a model for others to follow. A rigorous, meaningful group review can occur in 1 hour using a combination of group and individual activities focused on matching review criteria to the submitted manuscript. As a result, we continue to include GPR in future offerings of this interprofessional course on educational scholarship, and we continue to study ways to optimize its value as a service learning experience.

A Simple Phosphate-Buffered-Saline-Based Extraction Method Improves Specificity of HIV Viral Load Monitoring Using Dried Blood Spots.

Although Roche COBAS Ampliprep/COBAS TaqMan (CAP/CTM) systems are widely used in sub-Saharan Africa for early infant diagnosis of HIV from dried blood spots (DBS), viral load monitoring with this system is not practical due to nonspecific extraction of both cell-free and cell-associated viral nucleic acids. A simplified DBS extraction technique for cell-free virus elution using phosphate-buffered saline (PBS) may provide an alternative analyte for lower-cost quantitative HIV virus load (VL) testing to monitor antiretroviral therapy (ART). We evaluated the CAP/CTM v2.0 assay in 272 paired plasma and DBS specimens using the cell-free virus elution method and determined the level of agreement, sensitivity, and specificity at thresholds of target not detected (TND), target below the limit of quantification (BLQ) (<20 copies/ml in plasma or <400 copies/ml in DBS), and VL of <1,000 copies/ml, and VL of <5,000 copies/ml. Reported plasma VL ranged from TND, or <20, to 5,781,592 copies/ml, and DBS VL ranged from TND, or <400, to 467,600 copies/ml. At <1000 copies/ml, agreement between DBS and plasma was 96.7% (kappa coefficient, 0.93; P < 0.0001). The mean difference between DBS and plasma VL values was -1.06 log10 copies/ml (95% confidence interval [CI], -1.17, -0.97; P < 0.0001). At a treatment failure threshold of >1,000 copies/ml, the sensitivities, specificities, positive predictive values (PPV), and negative predictive values (NPV) were 92.7%, 100%, 100%, and 94.3%, respectively. PBS elution of DBS offers a sensitive and specific method for monitoring plasma viremia among adults and children on ART at the WHO-recommended threshold of >1,000 copies/ml on the Roche CAP/CTM system.

Periodic nonlinear sliding modes for two uniformly magnetized spheres.

A uniformly magnetized sphere slides without friction along the surface of a second, identical sphere that is held fixed in space, subject to the magnetic force and torque of the fixed sphere and the normal force. The free sphere has two stable equilibrium positions and two unstable equilibrium positions. Two small-amplitude oscillatory modes describe the sliding motion of the free sphere near each stable equilibrium, and an unstable oscillatory mode describes the motion near each unstable equilibrium. The three oscillatory modes remain periodic at finite amplitudes, one bifurcating into mixed modes and circumnavigating the free sphere at large energies. For small energies, the free sphere is confined to one of the two discontiguous domains, each surrounding a stable equilibrium position. At large energies, these domains merge and the free sphere may visit both positions. The critical energy at which these domains merge coincides with the cumulation point of an infinite cascade of mixed-mode bifurcations. These findings exploit the equivalence of the force and torque between two uniformly magnetized spheres and the force and torque between two equivalent point dipoles, and offer clues to the rich nonlinear dynamics of this system. Online MagPhyx visualizations illustrate the dynamics.

Writing competitive research conference abstracts: AMEE Guide no. 108.

The ability to write a competitive research conference abstract is an important skill for medical educators. A compelling and concise abstract can convince peer reviewers, conference selection committee members, and conference attendees that the research described therein is worthy for inclusion in the conference program and/or for their attendance in the meeting. This AMEE Guide is designed to help medical educators write research conference abstracts that can achieve these outcomes. To do so, this Guide begins by examining the rhetorical context (i.e. the purpose, audience, and structure) of research conference abstracts and then moves on to describe the abstract selection processes common to many medical education conferences. Next, the Guide provides theory-based information and concrete suggestions on how to write persuasively. Finally, the Guide offers some writing tips and some proofreading techniques that all authors can use. By attending to the aspects of the research conference abstract addressed in this Guide, we hope to help medical educators enhance this important text in their writing repertoire.

How students experience and navigate transitions in undergraduate medical education: an application of Bourdieu's theoretical model.

Using Bourdieu's theoretical model as a lens for analysis, we sought to understand how students experience the undergraduate medical education (UME) milieu, focusing on how they navigate transitions from the preclinical phase, to the major clinical year (MCY), and to the preparation for residency phase. Twenty-two medical students participated in this longitudinal case study. Students had similar preclinical and post-MCY experiences but different MCY experiences (rotational vs. longitudinal tracks). We interviewed students every 6 months in the preclinical phase, mid-way through MCY, and 7-8 months before graduation (101 total interviews). We inductively created codes, iteratively revised codes to best-fit the data, and thematically clustered codes into Bourdieu-informed categories: field (social structures), capital (resources) and habitus (dispositions). We found that students acclimated to shifts in the UME field as they moved through medical school: from medical school itself to the health system and back. To successfully navigate transitions, students learned to secure capital as medical knowledge and social connections in the preclinical and preparation for residency phases, and as reputable patient care and being noticed in the clinical phase. To obtain capital, and be well-positioned for the next phase of training, students consistently relied on dispositions of initiative and flexibility. In summary, students experience the complex context of medical school through a series of transitions. Efforts to improve UME would be well-served by greater awareness of the social structures (field) that students encounter, the resources to which they afford value (capital), and the dispositions which aid acquisition of these resources (habitus).

"Where Does the Circle End?": Representation as a Critical Aspect of Reflection in Teaching Social and Behavioral Sciences in Medicine.

OBJECTIVE: This paper describes a reflective learning program within a larger curriculum on behavioral and social science that makes use of close reading, written representation of experience, discussion, and textual response. This response may in turn lead to further reflection, representation, and response in a circular pattern. A unique feature of this program is that it pays attention to the representation itself as the pivotal activity within reflective learning. Using the narrative methods that are the hallmark of this program, faculty writings were analyzed to characterize the essential benefits that derive from these practices. METHODS: In the context of a faculty development seminar on the teaching of behavioral and social sciences in medical curricula, a group of 15 faculty members wrote brief narratives of reflective learning experiences in which they had made use of the methods described above. Their responses were submitted to iterative close reading and discussion, and potential themes were identified. RESULTS: Four themes emerged: writing as attention to self, writing as attention to other, writing as reader/writer contract, and writing as discovery. In each instance, writing provides a new or deepened perspective, and in each case, the dividends for the writer are amplified by the narrative skills of those who read, listen, and respond. CONCLUSIONS: The narrative pedagogy described and modeled herein provides a potentially promising approach to teaching the social, cultural, behavioral, and interpersonal aspects of medical education and practice. Future research will deepen our understanding of the benefits and limitations of this pedagogy and expand our appreciation of its applications.

Designing a Situational Judgment Test for Use in Medical School Admissions.

ABSTRACT: It has long been acknowledged that professional competencies are required for success in medical school, residency training, and medical practice. Over the last decade, medical schools have begun to introduce standardized assessments of professional competencies, but many still rely on interviews to assess these competencies, which occur after about half of the applicant pool has already been screened out. In this article, the authors discuss the development, evaluation, and launch of the Association of American Medical Colleges (AAMC) situational judgment test (SJT) for use in medical school admissions. The AAMC SJT is designed to assess an examinee's understanding of effective and ineffective behaviors related to the core competencies for entering medical students, including service orientation, social skills, cultural competence, teamwork, ethical responsibility to self and others, reliability and dependability, resilience and adaptability, and capacity for improvement. The authors evaluate the evidence for the need for SJTs in medical school admissions by exploring common derailers in medical school, gaps in the admissions process regarding information about professional competencies, and the challenge of conducting holistic review in a high-volume context. They summarize existing research from the employment, international medical education, and residency selection contexts suggesting that SJT scores are positively associated with subsequent performance and may add value to the admissions process. The authors discuss 5 goals that were the foundation for developing the AAMC SJT: (1) assess the professional competencies needed for success in medical school using a proven method, (2) enable holistic review in a high-volume admissions context, (3) create and share a program of research to support the appropriate use of SJT scores, (4) signal the need for preparation in professionalism to learners, and (5) balance the need for a new assessment with minimizing the burden and risk for applicants.

PBL and beyond: trends in collaborative learning.

Building upon the disruption to lecture-based methods triggered by the introduction of problem-based learning, approaches to promote collaborative learning are becoming increasingly diverse, widespread and generally well accepted within medical education. Examples of relatively new, structured collaborative learning methods include team-based learning and just-in-time teaching. Examples of less structured approaches include think-pair share, case discussions, and the flipped classroom. It is now common practice in medical education to employ a range of instructional approaches to support collaborative learning. We believe that the adoption of such approaches is entering a new and challenging era. We define collaborate learning by drawing on the broader literature, including Chi's ICAP framework that emphasizes the importance of sustained, interactive explanation and elaboration by learners. We distinguish collaborate learning from constructive, active, and passive learning and provide preliminary evidence documenting the growth of methods that support collaborative learning. We argue that the rate of adoption of collaborative learning methods will accelerate due to a growing emphasis on the development of team competencies and the increasing availability of digital media. At the same time, the adoption collaborative learning strategies face persistent challenges, stemming from an overdependence on comparative-effectiveness research and a lack of useful guidelines about how best to adapt collaborative learning methods to given learning contexts. The medical education community has struggled to consistently demonstrate superior outcomes when using collaborative learning methods and strategies. Despite this, support for their use will continue to expand. To select approaches with the greatest utility, instructors must carefully align conditions of the learning context with the learning approaches under consideration. Further, it is critical that modifications are made with caution and that instructors verify that modifications do not impede the desired cognitive activities needed to support meaningful collaborative learning.

Measuring the Learning Orientation Fostered by Pediatric Residency Programs With the Graduate Medical Education Learning Environment Inventory Instrument.

INTRODUCTION: Mastery learning orientation, conceptualized as a growth mindset, can be beneficial to learners in medical education and is supported by a program...s learning environment. Currently, there are no instruments which reliably assess the learning orientation of a graduate medical education program...s learning environment. OBJECTIVE: To explore the reliability and validity of the Graduate Medical Education Learning Environment Inventory (GME-LEI). METHODS: Leaders of the Education in Pediatrics Across the Continuum (EPAC) project revised Krupat...s Educational Climate Inventory to create the GME-LEI. We investigated the GME-LEI...s reliability and validity through confirmatory factor and parallel factor analyses and calculated Cronbach...s alpha for each subscale. We compared mean subscale scores between residents in traditional programs and the EPAC project. As EPAC is known to foster a mastery-focused learning orientation, we hypothesized differences detected between resident groups would strengthen the instrument...s validity. RESULTS: One hundred and twenty-seven pediatric residents completed the GME-LEI. The final 3-factor model was an acceptable fit to the data, and Cronbach...s alpha for each subscale was acceptable (Centrality: 0.87; Stress: 0.73; Support: 0.77). Mean scores on each subscale varied by program type (EPAC vs traditional) with EPAC residents reporting statistically significant higher scores in the Centrality of Learning subscale (2.03, SD 0.30, vs 1.79, SD 0.42; P.ß=.ß.023; scale of 1...4). CONCLUSIONS: The GME-LEI reliably measures 3 distinct aspects of the GME learning environment with respect to learning orientation. The GME-LEI may be used to help programs better monitor the learning environment and make changes to support mastery-oriented learning.

The Effect of Preoperative Symptom Duration on Patient-Reported Outcomes After Anterior Cervical Discectomy and Fusion in Nonmyelopathic Patients: Analyses From the Michigan Spine Surgery Improvement Collaborative (MSSIC).

BACKGROUND: The effect of preoperative symptom duration (PSD) on patient-reported outcomes (PROs) in anterior cervical discectomy and fusion (ACDF) for radiculopathy is unclear. OBJECTIVE: To determine whether PSD is a predictor for PRO after ACDF for radiculopathy. METHODS: The Michigan Spine Surgery Improvement Collaborative registry was queried between March, 2014, and July, 2019, for patients who underwent ACDF without myelopathy and PROs (baseline, 90 days, 1 year, 2 years). PROs were measured by numerical rating scales for neck/arm pain, Patient-Reported Outcomes Measurement Information System Short Form-Physical Function (PROMIS-PF), EuroQol-5D (EQ5D), and North American Spine Society satisfaction. Univariate analyses were used to evaluate the proportion of patients reaching minimal clinically important differences (MCID). PSD was <3 months, 3 month-1 year, or >1 years. Multiple logistic regression models were used to estimate the association between PSD and PRO reaching MCID. The discriminative ability of the model was evaluated by receiver operating characteristic curve. RESULTS: We included 2233 patients who underwent ACDF with PSD <3 months (278, 12.4%), 3 month-1 year (669, 30%), and >1 years (1286, 57.6%). Univariate analyses demonstrated a greater proportion of patients achieving MCID in <3-month cohort for arm numerical rating scales, PROMIS-PF, EQ5D, and North American Spine Society Satisfaction. Multivariable analyses demonstrated using <3 months PSD as a reference, PSD >1 years was associated with decreased odds of achieving MCID for EQ5D (odds ratio 0.5, CI 0.32-0.80, P = .004). Private insurance and increased baseline PRO were associated with significantly higher odds for achieving PROMIS-PF MCID and EQ5D-MCID. CONCLUSION: Preoperative symptom duration greater than 1 year in patients who underwent ACDF for radiculopathy was associated with worse odds of achieving MCID for multiple PROs.

Faculty development as transformation: lessons learned from a process-oriented program.

BACKGROUND: Faculty development programs tend to be oriented around content, yet many have produced positive outcomes unrelated to the content. We describe a faculty development program that utilized the processes of shared reading and guided reflection espoused by narrative medicine. DESCRIPTION: To date, 25 preceptors in the Foundations of Clinical Medicine course have participated. The program consists of weekly seminars in which participants actively engage with text as a basis for conversation around content as well as teaching strategies. EVALUATION: Using qualitative methods, we examined notes from seminars, in-depth interviews, and review of curricular documents; we used conceptual frameworks from education as interpretive lenses. Participants recognized both personal growth and transformation in relationships with each other, which created the opportunity, and the means, to address and reshape norms and teaching practices at the institution. CONCLUSIONS: Process-oriented faculty development programs may foster growth of individuals, contribute to transformation in relationships, and ultimately influence teaching practices.

Development of A Multi-Modality Navigational Based Training System for Fetoscopic Surgical Therapy.

Fetal surgery is regarded as a technically difficult and new field of research, requiring the use of fetoscopic and ultrasound (US) navigation to perform minimally invasive procedures within the amniotic cavity. The Surgical Apprenticeship Training model (SAT) centres around the subjective assessment of a surgical resident's cognitive competency and technical skills under proctorship using opportunity-based environments. The restrictiveness and rarity of fetal procedures limit the effectiveness of the SAT model, resulting in a slow learning curve (LC) and higher procedural complication rates. This paper aimed to investigate the use of optical tracking technology to construct a novel simulated training system and accompanying scoring assessment under the Proficiency-Based Training model (PBT), providing real-time positional feedback of surgical tools and a quantitative feedback assessment of a surgical resident's technical skills. Clinical Relevance- Clinical feedback deemed the system as valid and confirmed that this novel approach to surgical training will significantly benefit smaller clinics that lack opportunity-based environments. Clinical feedback also suggested that the training system could be adapted to provide access to complex surgical training across the world.

Documenting Educational Impact in the Promotion Dossier with an Enhanced Curriculum Vitae.

ABSTRACT: Faculty with a career focus on education in the health professions often have difficulty representing their academic accomplishments for due consideration in promotion decisions at their respective institutions. This problem occurs because the traditional curriculum vitae (CV) format which is most often used tends to focus on peer-reviewed accomplishments easily presented in lists, such as grants and publications. In some institutions, an educator portfolio is required in place of or in addition to the CV. However, creating or reviewing such a narrative-oriented document takes large amounts of time-time that most faculty or reviewers do not have. Having to use an educator portfolio also calls out the educator as different from the traditional research faculty member. To address this problem, we propose the solution of an Enhanced CV. The Enhanced CV includes much of what is presented in an educator portfolio but in a format closer to the traditional CV. Unlike a traditional CV, the Enhanced CV includes categories inclusive of educational contributions (eg, teaching, mentoring, and course leadership) and includes brief descriptions and/or impact statements to clarify the significance of the listed accomplishments. The Enhanced CV has been adopted at two very different institutions, where evidence is accumulating regarding the viability of the Enhanced CV as a solution to educators' problem of presenting their accomplishments for promotions. The lessons learned from these institutions illustrate how the Enhanced CV can increase the ability of educators to present their accomplishments and advance in rank in their academic careers.

Age as a Risk Factor for Complications Following Anterior Cervical Discectomy and Fusion: Analysis From the Michigan Spine Surgery Improvement Collaborative (MSSIC).

STUDY DESIGN: Retrospective analysis of prospectively collected registry data using multivariable analyses of imputed data. OBJECTIVE: We sought to demonstrate that age would not be associated with complications in patients undergoing anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Elderly patients (≥70 yrs) undergoing ACDF are considered a higher risk for complications. However, conclusive evidence is lacking. The Michigan Spine Surgery Improvement Collaborative (MSSIC) is a quality improvement collaborative with 30 hospitals across Michigan. METHODS: The study included all patients who had 1 to 4 level ACDF (September 2015-August 2019) for 90-day complications. Major and minor complications were defined using a validated classification. Multiple imputations were used to generate complete covariate datasets. Generalized estimating equation model was used to identify associations with complications using the whole cohort and elderly subgroup analyses. Bonferroni correction was used. RESULTS: Nine thousand one hundred thirty five patients (11.1% ≥ 70 yrs and 88.9% <70 yrs) with 2266 complications were analyzed. Comparing elderly versus non-elderly, the elderly had a significantly higher rate of any complications (31.5% vs. 24.0%, P < 0.001) and major complications (14.1% vs. 7.0%, P < 0.001). On multivariable analysis, age was not independently associated with any complication. POD#0 ambulation and preop independent ambulation were independently associated with significantly decreased odds of any complication. In the elderly, independent preoperative ambulation was protective for any complication (odds ratio [OR] 0.53, 0.39-0.73 95% confidence interval [CI]), especially major complications (OR 0.41, 0.27-0.61 95% CI). CONCLUSION: Age was not an independent risk factor for complications in patients that underwent ACDF. In the elderly, independent preoperative ambulation was especially protective for major complications.Level of Evidence: 3.