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OBJECTIVE Extension fractures in the setting of diffuse idiopathic skeletal hyperostosis (DISH) represent highly unstable injuries. As a result, these fractures are most frequently treated with immediate surgical fixation to limit any potential risk of associated neurological injury. Although this represents the standard of care, patients with significant comorbidities, advanced age, or medical instability may not be surgical candidates. In this paper, the authors evaluated a series of patients with extension DISH fractures who were treated with orthosis alone and evaluated their outcomes. METHODS A retrospective review from 2015 to 2022 was conducted at a large level 1 trauma center. Patients with extension-type DISH fractures without neurological deficits were identified. All patients were treated conservatively with orthosis alone. Baseline patient characteristics and adverse outcomes are reported. RESULTS Twenty-seven patients were identified as presenting with extension fractures associated with DISH without neurological deficit. Of these, 22 patients had complete follow-up on final chart review. Of these 22 patients, 21 (95.5%) were treated successfully with external orthosis. One patient (4.5%) who was noncompliant with the brace had an acute spinal cord injury 1 month after presentation, requiring immediate surgical fixation and decompression. No other complications, including skin breakdown or pressure ulcers related to bracing, were reported. CONCLUSIONS Treatment of extension-type DISH fractures may be a reasonable option for patients who are not candidates for safe surgical intervention; however, a risk of neurological injury secondary to delayed instability remains, particularly if patients are noncompliant with the bracing regimen. This risk should be balanced against the high complication rate and potential mortality associated with surgical intervention in this patient population.

Background: Vagus nerve stimulation (VNS) is regularly used to treat a variety of neurological disorders that impact the central nervous system (CNS). There are, however, few large animal models that allow for detailed mechanistic studies of the effects of VNS on the CNS during behavior. Methods: To that end, we describe the anatomical organization, surgical methodology to implant VNS electrodes and characterization of target engagement/neural interface properties in a non-human primate (NHP) model of VNS that permits chronic stimulation over long periods of time. Furthermore, we demonstrate the utility of this preparation in low n, proof of concept behavioral and imaging experiments investigating the effects of VNS on the CNS. Results: VNS electrode impedance remained constant over months suggesting a stable interface. VNS elicited robust activation of the vagus nerve which resulted in decreases of respiration rate and/or partial pressure of carbon dioxide in expired air, but not changes in heart rate in both awake and anesthetized NHPs. Conclusions: We anticipate that this preparation will be very useful to study the mechanisms underlying the effects of VNS for the treatment of conditions such as epilepsy and depression, for which VNS is extensively used, as well as for the study of the neurobiological basis underlying higher order functions such as learning and memory.

Background Finding the optimal location for the implantation of the electrode in deep brain stimulation (DBS) surgery is crucial for maximizing the therapeutic benefit to the patient. Such targeting is challenging for several reasons, including anatomic variability between patients as well as the lack of consensus about the location of the optimal target. Objective To compare the performance of popular manual targeting methods against a fully automatic nonrigid image registration-based approach. Methods In 71 Parkinson disease subthalamic nucleus (STN)-DBS implantations, an experienced functional neurosurgeon selected the target manually using 3 different approaches: indirect targeting using standard stereotactic coordinates, direct targeting based on the patient magnetic resonance imaging, and indirect targeting relative to the red nucleus. Targets were also automatically predicted by using a leave-one-out approach to populate the CranialVault atlas with the use of nonrigid image registration. The different targeting methods were compared against the location of the final active contact, determined through iterative clinical programming in each individual patient. Results Targeting by using standard stereotactic coordinates corresponding to the center of the motor territory of the STN had the largest targeting error (3.69 mm), followed by direct targeting (3.44 mm), average stereotactic coordinates of active contacts from this study (3.02 mm), red nucleus-based targeting (2.75 mm), and nonrigid image registration-based automatic predictions using the CranialVault atlas (2.70 mm). The CranialVault atlas method had statistically smaller variance than all manual approaches. Conclusion Fully automatic targeting based on nonrigid image registration with the use of the CranialVault atlas is as accurate and more precise than popular manual methods for STN-DBS.

Background Trigeminal neurovascular contact (NVC) is hypothesized to be the etiology of classical trigeminal neuralgia (TGN). We aimed to seek a correlation between types of NVCs and the presence of TGN as well as early surgical outcome in patients with TGN treated with trigeminal microvascular decompression (MVD). Methods We blindly analyzed preoperative high-resolution magnetic resonance images with respect to the degree (none, "touch," or compression) and location of bilateral NVC in 57 retrospectively identified Burchiel Type 1 TGN patients treated by MVD. Location of NVC was noted as either at the root entry zone or distal to it. Using a logistic regression model, we assessed the degree and location of trigeminal NVC for correlation with the symptomatic side. Furthermore, the NVC characteristics on the symptomatic side were correlated with early postoperative pain relief. Results Although the degree and location of NVC were not statistically correlative independently, a combined interaction analysis of both statistically correlated with the symptomatic side and with early postoperative pain relief. Conclusions We conclude that in TGN patients treated with MVD, magnetic resonance imaging identified neurovascular compression at the root entry zone (correlates with the affected side and early postoperative pain relief.

The crystallization and melting characteristics of a series of polyamide blends based on PA 4,6 and PA 6I were investigated by calorimetric methods; preparation of the samples was conducted so as to control the extent of transamidation occurring in the melt before crystallization. Blend samples with minimal prior thermal history displayed a modest degree of melting point depression compared to the equilibrium melting temperature of PA 4,6 (T = 309.5°C). Application of the Nishi–Wang equation indicated a value of χ = −0.25 for the blends. PA 4,6 and the blends followed Avrami crystallization kinetics with exponents in the range 2.0 to 2.5; no systematic variation of n with blend composition was observed. The influence of transamidation was investigated for samples exposed to varying melt temperatures and melt times with the extent of transreaction quantified using 13C-NMR. Increasing extents of transreaction led to a decrease in both the rate of crystallization and the overall bulk crystallinity of the blends owing to a reduction in the length and number of crystallizable blocks present along the polymer chains. Capillary rheometry studies indicated a strong sensitivity to time in the melt for the PA 4,6 homopolymer, and the mechanism responsible for the observed decrease in apparent viscosity was also operative in the blend samples. As such, it was not possible to independently assess the influence of transreaction on the rheology of the blends. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1245–1252, 2004