Diffusion MRI Metrics Characterize Postoperative Clinical Outcomes After Surgery for Cervical Spondylotic Myelopathy.

BACKGROUND AND OBJECTIVES: Advanced diffusion-weighted MRI (DWI) modeling, such as diffusion tensor imaging (DTI) and diffusion basis spectrum imaging (DBSI), may help guide rehabilitation strategies after surgical decompression for cervical spondylotic myelopathy (CSM). Currently, however, postoperative DWI is difficult to interpret, owing to signal distortions from spinal instrumentation. Therefore, we examined the relationship between postoperative DTI/DBSI-extracted from the rostral C3 spinal level-and clinical outcome measures at 2-year follow-up after decompressive surgery for CSM. METHODS: Fifty patients with CSM underwent complete clinical and DWI evaluation-followed by DTI/DBSI analysis-at baseline and 2-year follow-up. Clinical outcomes included the modified Japanese Orthopedic Association score and comprehensive patient-reported outcomes. DTI metrics included apparent diffusion coefficient, fractional anisotropy, axial diffusivity, and radial diffusivity. DBSI metrics evaluated white matter tracts through fractional anisotropy, fiber fraction, axial diffusivity, and radial diffusivity as well as extra-axonal pathology through restricted and nonrestricted fraction. Cross-sectional Spearman's correlations were used to compare postoperative DTI/DBSI metrics with clinical outcomes. RESULTS: Twenty-seven patients with CSM, including 15, 7, and 5 with mild, moderate, and severe disease, respectively, possessed complete baseline and postoperative DWI scans. At 2-year follow-up, there were 10 significant correlations among postoperative DBSI metrics and postoperative clinical outcomes compared with 3 among postoperative DTI metrics. Of the 13 significant correlations, 7 involved the neck disability index (NDI). The strongest relationships were between DBSI axial diffusivity and NDI (r = 0.60, P < .001), DBSI fiber fraction and NDI (rs = -0.58, P < .001), and DBSI restricted fraction and NDI (rs = 0.56, P < .001). The weakest correlation was between DTI apparent diffusion coefficient and NDI (r = 0.35, P = .02). CONCLUSION: Quantitative measures of spinal cord microstructure after surgery correlate with postoperative neurofunctional status, quality of life, and pain/disability at 2 years after decompressive surgery for CSM. In particular, DBSI metrics may serve as meaningful biomarkers for postoperative disease severity for patients with CSM.

Feasibility of postoperative diffusion-weighted imaging to assess representations of spinal cord microstructure in cervical spondylotic myelopathy.

OBJECTIVE: Diffusion basis spectrum imaging (DBSI) has shown promise in evaluating cervical spinal cord structural changes in patients with cervical spondylotic myelopathy (CSM). DBSI may also be valuable in the postoperative setting by serially tracking spinal cord microstructural changes following decompressive cervical spine surgery. Currently, there is a paucity of studies investigating this topic, likely because of challenges in resolving signal distortions from spinal instrumentation. Therefore, the objective of this study was to assess the feasibility of DBSI metrics extracted from the C3 spinal level to evaluate CSM patients postoperatively. METHODS: Fifty CSM patients and 20 healthy controls were enrolled in a single-center prospective study between 2018 and 2020. All patients and healthy controls underwent preoperative and postoperative diffusion-weighted MRI (dMRI) at a 2-year follow-up. All CSM patients underwent decompressive cervical surgery. The modified Japanese Orthopaedic Association (mJOA) score was used to categorize CSM patients as having mild, moderate, or severe myelopathy. DBSI metrics were extracted from the C3 spinal cord level to minimize image artifact and reduce partial volume effects. DBSI anisotropic tensors evaluated white matter tracts through fractional anisotropy, axial diffusivity, radial diffusivity, and fiber fraction. DBSI isotropic tensors assessed extra-axonal pathology through restricted and nonrestricted fractions. RESULTS: Of the 50 CSM patients, both baseline and postoperative dMR images with sufficient quality for analysis were obtained in 27 patients. These included 15 patients with mild CSM (mJOA scores 15-17), 7 with moderate CSM (scores 12-14), and 5 with severe CSM (scores 0-11), who were followed up for a mean of 23.5 (SD 4.1, range 11-31) months. All preoperative C3-level DBSI measures were significantly different between CSM patients and healthy controls (p < 0.05), except DBSI fractional anisotropy (p = 0.31). At the 2-year follow-up, the same significance pattern was found between CSM patients and healthy controls, except DBSI radial diffusivity was no longer statistically significant (p = 0.75). When assessing change (i.e., postoperative - preoperative values) in C3-level DBSI measures, CSM patients exhibited significant decreases in DBSI radial diffusivity (p = 0.02), suggesting improvement in myelin integrity (i.e., remyelination) at the 2-year follow-up. Among healthy controls, there was no significant difference in DBSI metrics over time. CONCLUSIONS: DBSI metrics derived from dMRI at the C3 spinal level can be used to provide meaningful insights into representations of the spinal cord microstructure of CSM patients at baseline and 2-year follow-up. DBSI may have the potential to characterize white matter tract recovery and inform outcomes following decompressive cervical surgery for CSM.

The life and legacy of John Robert Cobb: the man behind the angle.

In 1934, Dr. John Robert Cobb moved to New York to serve as the Gibney Orthopedic Fellow at the Hospital for the Ruptured and Crippled, now known as the Hospital for Special Surgery. In this role, Cobb was faced with a unique task that would shape not only his personal career but also the fields of scoliosis and spine care: to design the first scoliosis specialty clinic. He critically reviewed the treatment methods for scoliosis outlined by prior pioneers in spine surgery and kept his own meticulous records of diagnoses, treatments, and radiographs. Cobb's work culminated in major contributions to spine surgery that are highly relevant to this day, including the Cobb angle and the Cobb elevator. In this detailed analysis of the career and academic legacy of Dr. John R. Cobb, the authors examine in detail the historical events surrounding Cobb's great contributions to spine surgery and their lasting impact on our specialty, as well as unique aspects of his personal life. This historical vignette constitutes the first comprehensive analysis of the life, career, and academic legacy of Dr. John R. Cobb, the man behind the angle.

Predictors of Postoperative Segmental and Overall Lumbar Lordosis in Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Consecutive Case Series.

STUDY DESIGN: Retrospective Case-Series. OBJECTIVES: Due to heterogeneity in previous studies, the effect of MI-TLIF on postoperative segmental lordosis (SL) and lumbar lordosis (LL) remains unclear. Therefore, we aim to identify radiographic factors associated with lordosis after surgery in a homogenous series of MI-TLIF patients. METHODS: A single-center retrospective review identified consecutive patients who underwent single-level MI-TLIF for grade 1 degenerative spondylolisthesis from 2015-2020. All surgeries underwent unilateral facetectomies and a contralateral facet release with expandable interbody cages. PROs included the ODI and NRS-BP for low-back pain. Radiographic measures included SL, disc height, percent spondylolisthesis, cage positioning, LL, PI-LL mismatch, sacral-slope, and pelvic-tilt. Surgeries were considered "lordosing" if the change in postoperative SL was ≥ +4° and "kyphosing" if ≤ -4°. Predictors of change in SL/LL were evaluated using Pearson's correlation and multivariable regression. RESULTS: A total of 73 patients with an average follow-up of 22.5 (range 12-61) months were included. Patients experienced significant improvements in ODI (29% ± 22% improvement, P < .001) and NRS-BP (3.3 ± 3 point improvement, P < .001). There was a significant increase in mean SL (Δ3.43° ± 4.37°, P < .001) while LL (Δ0.17° ± 6.98°, P > .05) remained stable. Thirty-eight (52%) patients experienced lordosing MI-TLIFs, compared to 4 (5%) kyphosing and 31 (43%) neutral MI-TLIFs. A lower preoperative SL and more anterior cage placement were associated with the greatest improvement in SL (ß = -.45° P = .001, ß = 15.06° P < .001, respectively). CONCLUSIONS: In our series, the majority of patients experienced lordosing or neutral MI-TLIFs (n = 69, 95%). Preoperative radiographic alignment and anterior cage placement were significantly associated with target SL following MI-TLIF.

Expert Witness Testimony in Spine Surgery: A Review of Guidelines and Recommendations From Professional Organizations.

BACKGROUND: Most professional spine societies have enacted formal guidelines for spine surgeons providing expert witness services. However, there is significant heterogeneity in existing recommendations, with most societies providing information that is limited in detail and scope. OBJECTIVE: To provide a review of guidelines published by professional spine societies for spine surgeons serving as expert witnesses. METHODS: The Gale Directory Library, PubMed, and the grey literature were queried for national or international professional societies related to spine surgery. The search was focused on societies in the United States and North America, but also included well recognized international organizations in the field of spine surgery. Included societies with publicly available guidelines regarding expert witness services were extracted for 4 domains: (1) qualifications, (2) preparations, (3) testimony, and (4) compensation as well as the presence of a professional compliance program, defined as any official subcommittee aimed toward investigating claims of unethical behavior. RESULTS: Although most professional spine societies share general themes with respect to expert witness guidelines, important differences exist. Of the 26 societies included, 10 included publicly available guidelines: 4 of which were general neurosurgery societies, 2 general orthopedic surgery, and 4 spine specific. Three societies included the guidelines on all 4 domains (ie, qualifications, preparations, testimony, and compensation), and 2 societies included only 1 of the 4 domains. Eight societies possess a professional compliance program. CONCLUSION: There remains a paucity in expert witness guidelines provided by professional spine societies. Although existing recommendations are useful, there is a lack of standardized and comprehensive materials for spine surgeons providing expert witness testimony to reference. Moving forward, joint committees comprising surgeons, attorneys, and patient stakeholders may help improve the guidelines.

Blast-Related Traumatic Brain Injuries Secondary to Thermobaric Explosives: Implications for the War in Ukraine.

Blast-related traumatic brain injury (bTBI) is a significant cause of wartime morbidity and mortality. In recent decades, thermobaric explosives have emerged as particularly devastating weapons associated with bTBI. With recent documentation of the use of these weapons in the war in Ukraine, clinicians and laypersons alike could benefit from an improved understanding behind the dynamic interplay between explosive weaponry, its potential for bTBI, and the subsequent long-term consequences of these injuries. Therefore, we provide a general overview of the history and mechanism of action of thermobaric weapons and their potential to cause bTBI. In addition, we highlight the long-term cognitive and neuropsychiatric sequelae following bTBI and discuss diagnostic, therapeutic, and rehabilitation strategies, with the aim of helping to guide mitigation strategies and humanitarian relief in Ukraine. Thermobaric weapons produce a powerful blast wave capable of causing bTBIs, which can be further classified from primary to quaternary injuries. When modeling the hypothetical use of thermobaric weapons in Odessa, Ukraine, we estimate that the detonation of a salvo of thermobaric rockets has the potential to affect approximately 272 persons with bTBIs. In addition to the short-term damage, patients with bTBIs can present with long-term symptoms (e.g., post-traumatic stress disorder), which incur substantial financial costs and social consequences. Although these results are jarring, history has seen radical advancements in the understanding, diagnosis, and management of bTBI. Moving forward, a better understanding of the mechanism and long-term sequelae of bTBIs could help guide humanitarian relief to those affected by the war in Ukraine.

Political Rivalry During America's Founding Fathers Era and the Bullet that Ended Up in Alexander Hamilton's Upper Lumbar Spine.

On the morning of July 11, 1804, Major General Alexander Hamilton, an American statesman and one of the Founding Fathers of the United States, boarded a barge from Manhattan to the New Jersey shore. There, he met his personal and political opponent, Aaron Burr, for a duel during which Burr shot a bullet that entered Hamilton's torso, fractured a false rib, passed through internal organs, and lodged itself in one of his upper lumbar vertebrae. In this unique historical analysis of a pivotal event in American history, we provide a comprehensive discussion of the spinal injuries sustained by Alexander Hamilton, with special consideration of anatomic details and the ballistics of the time. To the authors' knowledge, this is the first thorough examination of the spinal injuries sustained by the prolific Founding Father and great mind behind the American financial system, Alexander Hamilton.