Longitudinal Outcomes of Cumulative Impact Exposure on Oculomotor Functioning in Professional Motorsport Drivers.

Importance: Professional motorsport drivers are regularly exposed to biomechanical forces comparable with those experienced by contact and collision sport athletes, and little is known about the potential short-term and long-term neurologic sequelae. Objective: To determine whether cumulative impact exposure is associated with oculomotor functioning in motorsport drivers from the INDYCAR professional open-wheel automobile racing series. Design, Setting, and Participants: This is a longitudinal retrospective cohort study conducted across 3 racing seasons (2017-2019). Statistical analyses were conducted in November 2021. Data were retrieved from a secondary care setting associated with the INDYCAR series. INDYCAR series drivers who participated in 3 professional level racing seasons and were involved in at least 1 contact incident (ie, crash) in 2 of the 3 seasons were included in the study. Exposure: Cumulative acceleration and deceleration forces and total contact incidents (ie, crashes) measured via accident data recorder third generation chassis and ear accelerometers. Main Outcomes and Measures: Postseries oculomotor performance, including predictive saccades, vergence smooth pursuit, and optokinetic nystagmus, was measured annually with a head-mounted, clinical eye tracking system (Neurolign Dx 100). Results: Thirteen drivers (mean [SD] age, 29.36 [7.82] years; all men) sustained median resultant acceleration forces of 38.15 g (observed range, 12.01-93.05 g; 95% CI, 30.62-65.81 g) across 81 crashes. A 2-way multivariate analysis of variance did not reveal a statistically significant association between ear and chassis average resultant g forces, total number of contact incidents, and racing season assessed (F9,12 = 0.955; P = .54; Wilks Λ = 0.44). Conclusions and Relevance: In this cohort study of professional drivers from the INDYCAR series, there were no statistically significant associations among cumulative impact exposure, racing season assessed, and oculomotor performance. Longitudinal studies across racing seasons using multidimensional examination modalities (eg, neurocognitive testing, advanced imaging, biomarkers, and physical examination) are critical to understand potential neurological and neurobehavioral sequelae and long-term consequences of cumulative impact exposure.

Guideline summary review: an evidence-based clinical guideline for the diagnosis and treatment of adult isthmic spondylolisthesis.

BACKGROUND CONTEXT: The North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Adult Isthmic Spondylolisthesis features evidence-based recommendations for diagnosing and treating adult patients with isthmic spondylolisthesis. The guideline is intended to reflect contemporary treatment concepts for symptomatic isthmic spondylolisthesis as reflected in the highest quality clinical literature available on this subject as of June 2013. NASS' guideline on this topic is the only guideline on adult isthmic spondylolisthesis accepted in the Agency for Healthcare Research and Quality's National Guideline Clearinghouse. PURPOSE: The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with isthmic spondylolisthesis. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition. STUDY DESIGN: This is a guideline summary review. METHODS: This guideline is the product of the Adult Isthmic Spondylolisthesis Work Group of NASS' Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questionsto address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guidelines were submitted to an internal peer review process and ultimately approved by the NASS Board of Directors. Upon publication, the Adult Isthmic Spondylolisthesis guideline was accepted into the National Guideline Clearinghouse and will be updated approximately every 5 years. RESULTS: Thirty-one clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature. CONCLUSIONS: The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with isthmic spondylolisthesis. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx and will remain updated on a timely schedule.

Radiation exposure as a consequence of spinal immobilization and extrication.

BACKGROUND: Extrication and spinal immobilization in the trauma patient with unknown injuries is a common practice of emergency medical services. High-speed crashes occurring in open-wheel racing seldom result in extrication or spinal immobilization. OBJECTIVES: To evaluate the safety of self-extrication in IndyCar® (Indianapolis, IN) by comparing drivers self extricated with full spinal immobilization and subsequent radiation exposure. METHODS: A retrospective review of prospectively collected de-identified IndyCar® crash and drivers' medical records was performed at treating Level I trauma centers. One hundred thirty-five crash incidents involving drivers evaluated by a medical team were included. Any driver with severe multiple trauma was excluded due to distracting injuries. Drivers underwent standard protocol for postcrash injury. Diagnostic and treatment outcomes including spinal and neurologic injury, need for surgery, and radiation exposure were collected for review. RESULTS: Self-extrication occurred in 121 (90%) crashes, and overall cumulative radiation exposure ranged from 100 to 250 mSv, or 0.82-2.06 mSv per driver. Extrication with full spinal immobilization occurred in 14 (10%) drivers, with overall cumulative radiation exposure ranging from 140 to 350 mSv, or 10-25 mSv per driver. A total of 29 injuries were identified, nine of which (31%) were spinal. In these, six were emergency medical services extricated and three self extricated. None were unstable spinal fractures resulting in surgical care, surgical disease, or neurologic deficit. CONCLUSION: In our IndyCar® racing experience, a protocol-led self-extrication system resulted in neither a mismanagement of an unstable spinal fracture nor neurological deficit, and reduced radiation exposure.

A comparison of MRI and CT imaging clarity of titanium alloy and titanium alloy with cobalt-chromium-alloy pedicle screw and rod implants in the lumbar spine.

BACKGROUND: Magnetic resonance imaging (MRI) and computed tomography (CT) imaging are important postoperative diagnostic and evaluation tools, particularly in patients who have undergone spinal fusions. Advancements in materials and imaging techniques have lessened artifact and improved overall imaging results. Systems that combine titanium alloy and cobalt-chromium components have been introduced to reduce implant profile while maintaining strength. The objective of this study was to determine if there were any differences in the clarity of imaging between two types of implant materials in a lumbar spine construct model. METHODS: One of two lumbar spine stabilization implant systems, titanium alloy (titanium) or titanium alloy with cobalt-chromium alloy (titanium-cobalt), was placed to simulate a four-level fusion construct in two human cadaveric spine segments, followed by MRI and CT imaging. The implant systems were then removed from each cadaver and implanted in the other cadaver. Nine physician graders from three subspecialties scored the images using a 5-point scale, with higher imaging scores indicating greater clarity of the region of interest. Physician-rated scores were compared across systems and between physician groups. RESULTS: There were no significant differences in the overall mean total scores on the basis of construct material. Overall mean scores were 18.16 for titanium and 17.45 for titanium-cobalt (p = 0.275). Among images of the titanium-cobalt constructs, no significant differences in mean scores were found between specimens with use of MRI (p = 0.883) or with use of CT only (p = 0.274). Among images of the titanium system, a slightly significant difference was found between specimens with use of MRI (p = 0.044) but not with CT imaging (p = 0.837). CONCLUSIONS: Overall image clarity scores were not significantly different between titanium and titanium-cobalt implant systems in the lumbar spine. Observation of pertinent anatomy in the regions of interest was not degraded by the presence of either system.

Comparison of single-level cervical fusion and a metal-on-metal cervical disc replacement device.

Cervical fusion is the common treatment for cervical disc disease but can cause secondary disorders. The Prestige ST cervical disc prosthesis (Medtronic Sofamor Danek, Memphis, TN) was designed to preserve spinal motion to potentially limit the secondary disorders. In this article, we report 2-year results from a single-center study comparing use of this device with use of anterior cervical discectomy and fusion (ACDF). Nineteen patients were prospectively randomized to receive the device or to undergo ACDF. Twenty-four months after surgery, patients who received the device demonstrated improvement in neck pain, arm pain, and neurologic function. In our cohort, patients who underwent arthroplasty demonstrated greater improvement in neurologic function and neck pain than patients who underwent cervical discectomy and fusion.

Pyogenic lumbar facet joint arthritis with intradural extension: a case report.

There have been 40 previously reported cases of lumbar facet joint pyogenic infection. These have been well characterized earlier. Intradural pyogenic extension has never been reported from a facet joint origin. This case demonstrates an elderly diabetic man with acute onset of nontraumatic back pain with no other source of infectious pathology. Surgical exploration identified a purulent left L4-L5 facet joint with epidural and intradural extension. Minimal spinal fluid leak was present. Wound cultures were positive for Group B beta Full resolution occurred with appropriate intravenous vancomycin antibiotic therapy.