The use of diffusion tensor imaging in spinal pathology: a comprehensive literature review.

STUDY DESIGN: We reviewed the available literature systematically without meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. OBJECTIVE: To evaluate contemporary literature on use of spinal diffusion tensor imaging(sDTI) in spinal pathology. BACKGROUND: sDTI reveals the location and functional state of critical long tracts and is a potentially useful adjunct in disease management. METHODS: Studies were included if they presented or discussed data from investigative or therapeutic procedures involving sDTI on human subjects in the setting of surgically amenable spinal pathology. Studies were excluded if they were (1) restricted to computational models investigating parameters using data not obtained clinically, (2) about cranial DTI methods, (3) about spinal pathology data not related to surgical management, (4) discussions or overviews of methods/techniques with minimal inclusion of objective experimental or clinical data. RESULTS: Degenerative pathologies of interest were restricted to either cervical myelopathy (22/29,75.9%) or lumbar spondylosis 7/29,24.1%). Mass-occupying lesions included intradural pathology and discussed preoperative (7/9,77.8%) and intraoperative imaging(2/9,22.2%) as an adjunct to surgery 22.2%. Traumatic pathology focused on spinal cord injury prognosis and severity grading. CONCLUSIONS: sDTI seems useful in surgical decision making and outcome measurements and in establishing clinical prognoses over a wide range of surgical pathologies. Further research is warranted with longer follow-up and larger population sizes in a prospective and controlled protocol.

Intrafacet Spacer Placement as a Mobility-Sparing Bailout Option in Atlantoaxial Fusion Construct Salvage.

Background: Salvage revisions of atlantoaxial (AA) joint complex posterior segmental instrumented fusion constructs require careful individualized planning to prevent occipital extension. In this case report, we describe the use of bilateral intrafacet spacer placement as a mobility-sparing bailout option for the revision surgery. Case Report: A 64-year-old male with a history of diffuse idiopathic skeletal hyperostosis, extremely limited baseline cervical mobility, and prior AA posterior segmental instrumented fusion presented with increasing pain at his 6-month follow-up. Imaging showed fusion and hardware failures and dynamic instability. To prevent occipitocervical fixation, AA intra-articular fusion via a DTRAX spinal system (Providence Medical Technology, Inc) was used as an adjunct to a navigated C1 lateral mass and C2 pars screw posterior segmental instrumented fusion construct. The patient had an uneventful postoperative course and was discharged with resolution of symptoms. Three-month postoperative follow-up confirmed persistent resolution of symptoms and absence of complaints, along with successful arthrodesis on imaging. Conclusion: AA posterior segmental instrumented fusion revision is technically challenging, particularly when partial preservation of craniovertebral junction mobility is required. Bilateral intra-articular cages may be used as an adjunct to hardware revision in construct salvage when sturdy arthrodesis is desired without occipital extension and may represent a major potential strength of intra-articular cages.

Training Cerebrovascular and Neuroendovascular Surgery Residents: A Systematic Literature Review and Recommendations.

Background: The rapid evolution of neuroendovascular intervention has resulted in the inclusion of endovascular techniques as a core competency in neurosurgical residency training. Methods: We conducted a literature review of studies involving the training of neurosurgical residents in cerebrovascular and endovascular neurosurgery. We reviewed the evolution of cerebrovascular neurosurgery and the effects of these changes on residency, and we propose interventions to supplement contemporary training. Results: A total of 48 studies were included for full review. Studies evaluated trainee education and competency (29.2%, 14/48), neuroendovascular training models (20.8%, 10/48), and open cerebrovascular training models (52.1%, 25/48), with some overlap. We used a qualitative analysis of reviewed reports to generate a series of suggested training supplements to optimize cerebrovascular education. Conclusion: Cerebrovascular neurosurgery is at a crossroads where trainees must develop disparate skill sets with inverse trends in volume. Continued longitudinal exposure to both endovascular and open cerebrovascular surgical fields should be mandated in general resident education, and blended learning tactics using adjunct simulation systems and models should be incorporated with didactics to both optimize learning and alleviate restraints placed by decreased volume and autonomy.

Are the Ethmoidal Foramina Through the Frontal Bone, Ethmoid Bone, or Frontoethmoidal Suture?

INTRODUCTION: To investigate the locations of the anterior, middle, and posterior ethmoidal foramina and their relationships to the frontoethmoidal suture. METHODS: One hundred twenty sides from sixty adult human skulls were used. Specimens with significant damage to the medial orbit wall were excluded. The number of ethmoidal foramina (anterior, middle, and posterior) on the medial orbital wall and the relationship of each foramen to the frontoethmoidal suture were recorded and classified as follows: Type I: superior to the frontoethmoidal suture; Type II: on the frontoethmoidal suture; Type III: inferior to the frontoethmoidal suture. RESULTS: Of the ninety-four sides, fourteen (14.9%) had one foramen, sixty-two (66.0%) had two , and eighteen (19.1%) had three. In total, 192 ethmoidal foramina were observed. Among the fourteen sides with one foramen, eight foramina were anterior and six were posterior. Among the 192 ethmoidal foramina, 162 were eligible for fur ther classification (74 anterior, 14 middle, and 74 posterior). Types I, II, and III ethmoidal foramina were found in 38.3% (62/162), 61.7% (100/162), and 0% (0/162), respectively. CONCLUSIONS: Our current study found a higher incidence of type I than previously reported. It is important to be aware of the significant incidence of foramen variations when the medial orbit wall is manipulated during surgery. Unless caution is observed, an inadvertent surgical injury can occur and lead to life-threatening complications. Therefore, a good understanding of orbital anatomy and its potential variations is critical for improving patient out comes.

Endovascular Mechanical Thrombectomy for Right Hemispheric Stroke Syndrome Due to Acute Left A1-A2 Junction Thromboembolic Occlusion.

Background: Endovascular mechanical thrombectomy (EVT) for large vessel occlusions has had a dramatic impact on the management of acute ischemic stroke. Extended use of EVT beyond American Heart Association guidelines has been successful in carefully selected cases. Case Report: A 71-year-old male presented to our comprehensive stroke center upon awakening with mild left hemiparesis. He was found to have a chronic occlusion of the right supraclinoid segment of the internal carotid artery. Angiography demonstrated large vessel occlusion of the contralateral A1-A2 junction that was successfully recanalized. Imaging at 24 hours displayed no evidence of infarct, the patient rapidly improved during hospitalization, and he was discharged on postoperative day 7 with a National Institutes of Health Stroke Scale score of zero. Conclusion: We describe successful EVT of a patient presenting with false-localizing symptoms consistent with a right hemispheric acute ischemic stroke secondary to left A1-A2 junction large vessel occlusion. This case demonstrates the importance of a high index of suspicion when evaluating atypical stroke presentations and the effectiveness of EVT in the treatment of distal small-caliber vessels.

Neonatal high-flow anterior circulation dural arteriovenous fistulae successfully treated with subtotal endovascular embolization; A case report.

High-flow grade-III dural arteriovenous fistulae(dAVF) represent rare abnormal vascular connections with a high risk of rupture. Management involves obliteration of both the fistulous connection as well as the draining venous network with preservation of normal vasculature. We describe and multiple neonatal dAVFs inducing cardiomyopathy via high-flow grade III shunting in the anterior circulation successfully treated via transvenous and transarterial embolization.

What is the C2 pedicle, pars interarticularis, and isthmus? Anatomical study and review of the literature regarding these confusing terms with proposal of new nomenclature.

INTRODUCTION: The atypical anatomy of the C2 vertebra has led to terminological discrepancies within reports and studies in the literature regarding the location of its pedicle, pars interarticularis, and isthmus. These discrepancies not only limit the power of morphometric analyses, but they also confuse technical reports regarding operations involving C2, and thus confuse our ability to properly communicate this anatomy. Herein, we examine the variations in nomenclature regarding the pedicle, pars interarticularis, and isthmus of C2, and via an anatomical study, propose new terminology. METHODS: The articular surface and underlying superior and inferior articular processes and adjacent transverse processes were removed from 15 C2 vertebrae (30 sides). Specifically, the areas regarded as the pedicle, pars interarticularis, and isthmus were evaluated. Morphometrics were performed. RESULTS: Our results indicate that, anatomically, C2 has no "isthmus" and that a pars interarticularis for C2, when present, is very short. Deconstruction of the attached parts allowed for visualization of a bony arch extending from the anterior most aspect of the lamina to the body of C2. The arch is composed almost entirely of trabecular bone and without its attached parts, e.g., transverse process, really has no cortical bone laterally. CONCLUSIONS: We propose a more accurate terminology, the pedicle, for pars/pedicle screw placement of C2. Such a term more accurately describes this unique structure of the C2 vertebra and would alleviate terminological confusion in the future literature on this topic.

Ventral Subaxial Cervical Access Using Tailored Access Osteotomies, A Cadaveric Study.

BACKGROUND: Ventral lesions of the subaxial cervical spine are challenging because approaches must circumvent endodermal and neurovascular structures. OBJECTIVE: To use cadaveric study to describe 4 posterolateral approaches to the ventral subaxial cervical spine with various facilitating techniques and osteotomies. METHODS: Three cadaveric specimens of the cervical spine were sequentially subjected to multilevel laminectomy (Type 1), transfacet (Type 2), transpedicular (Type 3), and extreme lateral transforaminal (Type 4) approaches. Approach working angles and proportion of visualized zones were compared, the former calculated using trigonometric methods. RESULTS: There was a significant stepwise increase in working angle in the ventral space, associated with increasing osteotomy type, from an average of 3.7° in single-level type 1 to 19.47° in the type 4 osteotomy. Regarding anatomic zones, proportional partial and total visualization achieved with Type 2 to 4 approaches were significantly greater than with Type 1. Complex osteotomies allowed superior access to be obtained to contributing and adjacent vessels of the ventral spinal axis. CONCLUSION: Ventral subaxial cervical lesions are difficult to access. We report increased working angles using quantified cadaveric data in increasingly complex posterior and posterolateral approaches graded as type 1 through 4. We advocate continued translational research in such approaches to lesions often considered to lie in surgically inaccessible locations.