Novel Nerve-Sparing In Situ Assembly of an Expandable Titanium Cage to Maximize Endplate Coverage After Posterior Corpectomy for Comminuted Lumbar Burst Fractures.

BACKGROUND AND OBJECTIVES: The ability to maximize corpectomy cage endcap size and vertebral endplate coverage after corpectomy for lumbar burst fractures (L1-L5) is limited by the presence of lumbar nerve roots and the larger cross-sectional area of the lumbar endplates relative to the restrictive corridor for cage insertion. This work aims to provide details and clinical examples of a novel operative technique for 3-column reconstruction and stabilization of comminuted lumbar burst fractures. METHODS: Through a standard posterior midline approach and following posterior instrumentation and lateral extracavitary corpectomy, an in-situ assembly of a modular corpectomy cage that respects adjacent neural structures, restores segmental alignment, and maximizes endplate coverage across a lordotic segment is completed. RESULTS: Radiographic evidence of anatomic spinal reconstruction and stabilization with complete or near-complete endplate coverage without incurrence of new clinical deficit after this novel treatment of lumbar burst fractures. CONCLUSION: The fixation approach described in this report may be a valuable modification to a long-standing technique used for treating comminuted lumbar burst fractures (L1-L5) from a posterior-only approach without incurring additional neurological deficits and by improving endplate and apophyseal ring coverage.

Transoral digital reduction of complete anterior odontoid dislocation followed by fiducial-based navigated transcondylar screw fixation: illustrative case.

BACKGROUND: Posterior atlantoaxial dislocations (i.e., complete anterior odontoid dislocation) without C1 arch fractures are a rare hyperextension injury most often found in high-velocity trauma patients. Treatment options include either closed or open reduction and optional spinal fusion to address atlantoaxial instability due to ligamentous injury. OBSERVATIONS: A 60-year-old male was struck while on his bicycle by a truck and sustained an odontoid dislocation without C1 arch fracture. Imaging findings additionally delineated a high suspicion for craniocervical instability. The patient had neurological issues due to both a head injury and ischemia secondary to an injured vertebral artery. He was stabilized and transferred to our facility for definitive neurosurgical care. LESSONS: The patient underwent a successful transoral digital closed reduction and posterior occipital spinal fusion via a fiducial-based transcondylar, C1 lateral mass, C2 pedicle, and C3 lateral mass construct. This unique reduction technique has not been recorded in the literature before and avoided potential complications of overdistraction and the need for odontoidectomy. Furthermore, the use of bone fiducials for navigated screw fixation at the craniocervical junction is a novel technique and recommended particularly for placement of technically demanding transcondylar screws and C2 pedicle screws where pars anatomy is potentially unfavorable.

Age-associated vasospasm in aneurysmal subarachnoid hemorrhage.

The relationship between age and vasospasm caused by subarachnoid hemorrhage (SAH) is controversial. We evaluated this relationship in a contemporary sample from a single institution. In a retrospective study design, we included patients with SAH caused by ruptured intracranial aneurysms. All patients underwent an evaluation that included head imaging, cerebral angiography, and treatment for the underlying aneurysm. Vasospasm was classified as absent, any vasospasm, or symptomatic vasospasm. Age was classified into 2 categories with a cutoff of 50 years, and also was stratified by decade. All patients had received preventative and therapeutic measures for vasospasm. Logistic regression analysis was used to assess the association between age and the occurrence of vasospasm. A total of 108 patients were included in this analysis, 67 of whom were age ≥50 years. The older patients had a higher incidence of vascular risk factors, and the younger patients had a higher incidence of smoking and illicit substance abuse. The mean age of the patients with any vasospasm (n = 41) was 48.51 ± 11.23 years, compared with 59.67 ± 13.30 years in those without vasospasm (P < .0001). Adjusted analysis found a greater risk of vasospasm in the younger patients compared with the older patients (odds ratio, 5.83; 95% confidence interval, 2.41-14.12 for any vasospasm; odds ratio, 2.66; 95% confidence interval, 1.008-7.052 for symptomatic vasospasm). This risk of vasospasm decreased with advanced age (P < .0001). Our findings suggest that patients age <50 years are at 5-fold greater risk of any vasospasm compared with older patients, and that age-adjusted prevention protocols may need to be considered.

Analysis of responses to valerian root extract in the feline pulmonary vascular bed.

OBJECTIVES: This study was undertaken to investigate pulmonary vascular response to valerian (Valeriana officinalis) in the feline pulmonary vasculature under constant flow conditions. DESIGN: In separate experiments, the effects of NG-L-nitro-L-arginine methyl ester (L-NIO), a nitric oxide synthase inhibitor, glibenclamide, an adenosine triphosphate (ATP)-sensitive potassium (K+) channel blocker, meclofenamate, a nonselective cyclooxygenase (COX) inhibitor, bicuculline, a GABA(A) receptor antagonist, and saclofen, a GABA(B) antagonist, were investigated on pulmonary arterial responses to various agonists in the feline pulmonary vascular bed. These agonists included valerian, muscimol, a GABA(A) agonist, SKF-97541 a GABA(B) agonist, acetylcholine (ACh), and bradykinin, both inducers of nitric oxide synthase, arachidonic acid, a COX substrate, and pinacidil, an ATP-sensitive K+ channel activator, during increased tone conditions induced by the thromboxane A2 mimic, U46619. SETTINGS/LOCATION: Laboratory investigation. SUBJECTS: Mongrel cats of either gender. INTERVENTIONS: Injections of the abovementioned agonists and antagonists were given. OUTCOME MEASURES: Baseline pulmonary tone, responses to the agonists, and responses to the agonists after injections of antagonists were all measured via a pulmonary catheter transducer and recorded. RESULTS: Valerian root extract is a potent smooth muscle dilator in the feline pulmonary vascular bed. The vasodilatory effects of valerian root extract were unchanged after the administration of L-NIO, glibenclamide, and meclofenamate. These effects were ablated, however, by both saclofen and bicuculline. The ability of saclofen and bicuculline to modulate the dilatory effects of valerian root extract was not statistically different. CONCLUSIONS: The vasodilatory effects of valerian root extract are mediated by a nonselective GABA mechanism.