Disruption of the Atrophy-based Functional Network in Multiple Sclerosis Is Associated with Clinical Disability: Validation of a Meta-Analytic Model in Resting-State Functional MRI.

Background In multiple sclerosis (MS), gray matter (GM) atrophy exhibits a specific pattern, which correlates strongly with clinical disability. However, the mechanism of regional specificity in GM atrophy remains largely unknown. Recently, the network degeneration hypothesis (NDH) was quantitatively defined (using coordinate-based meta-analysis) as the atrophy-based functional network (AFN) model, which posits that localized GM atrophy in MS is mediated by functional networks. Purpose To test the NDH in MS in a data-driven manner using the AFN model to direct analyses in an independent test sample. Materials and Methods Model fit testing was conducted with structural equation modeling, which is based on the computation of semipartial correlations. Model verification was performed in coordinate-based data of healthy control participants from the BrainMap database (https://www.brainmap.org). Model validation was conducted in prospectively acquired resting-state functional MRI in participants with relapsing-remitting MS who were recruited between September 2018 and January 2019. Correlation analyses of model fit indices and volumetric measures with Expanded Disability Status Scale (EDSS) scores and disease duration were performed. Results Model verification of healthy control participants included 80 194 coordinates from 9035 experiments. Model verification in healthy control data resulted in excellent model fit (root mean square error of approximation, 0.037; 90% CI: 0.036, 0.039). Twenty participants (mean age, 36 years ± 9 [standard deviation]; 12 women) with relapsing-remitting MS were evaluated. Model validation in resting-state functional MRI in participants with MS resulted in deviation from optimal model fit (root mean square error of approximation, 0.071; 90% CI: 0.070, 0.072), which correlated with EDSS scores (r = 0.68; P = .002). Conclusion The atrophy-based functional network model predicts functional network disruption in multiple sclerosis (MS), thereby supporting the network degeneration hypothesis. On resting-state functional MRI scans, reduced functional network integrity in participants with MS had a strong positive correlation with clinical disability. © RSNA, 2021 Online supplemental material is available for this article.

More Than 1 Way to Put in A T-Tube: A Review of Different Techniques Used in Insertion of Montgomery T-Tubes.

OBJECTIVE: The Montgomery T-tube is a commonly used device initially designed as a temporary airway stent, but also used as a long-term airway solution for stenosis. For patients undergoing either endoscopic or open airway procedures, proper techniques for inserting these tubes are well documented. This review compiles the techniques used for insertion of the Montgomery T-tube stent. METHODS: The NCBI Pubmed database was queried using the keywords: "stent," "Montgomery," "T-tube," "stenosis," "technique." A total of 33 papers were reviewed with 12 papers selected for the study. Papers were selected based on inclusion criteria of English language and whether the paper described a technique for insertion of a Montgomery T-tube into the airway. Papers were excluded if they did not describe the technique of insertion of Montgomery T-tubes or dealt with another aspect of T-tube management. RESULTS: The 12 selected papers each described a different technique for insertion of a Montgomery T-tube stent. Though nearly all the selected studies described using a modified Seldinger technique for insertion of the T-tube, there were discrepancies and a wide array of different instruments used. The instrument and/or technique that was selected was often determined by the individual need of the patient. Several studies addressed the challenge of interrupting ventilation while inserting or exchanging a T-tube in the operating room. These studies described attaching the T-tube to the endotracheal tube to pass the T-tube into the airway while allowing for continuous ventilation. Yet other studies used optical forceps or rigid bronchoscopes to allow placement of the T-tube with direct visualization. CONCLUSION: There are many techniques used for the insertion of a Montgomery T-tube. Nearly all studies described using a modified Seldinger technique and all the studies agreed on the necessity of a team approach for placement of the Montgomery T-tube.

A Contemporary Review of Trachea, Nose, and Ear Cartilage Bioengineering and Additive Manufacturing.

The complex structure, chemical composition, and biomechanical properties of craniofacial cartilaginous structures make them challenging to reconstruct. Autologous grafts have limited tissue availability and can cause significant donor-site morbidity, homologous grafts often require immunosuppression, and alloplastic grafts may have high rates of infection or displacement. Furthermore, all these grafting techniques require a high level of surgical skill to ensure that the reconstruction matches the original structure. Current research indicates that additive manufacturing shows promise in overcoming these limitations. Autologous stem cells have been developed into cartilage when exposed to the appropriate growth factors and culture conditions, such as mechanical stress and oxygen deprivation. Additive manufacturing allows for increased precision when engineering scaffolds for stem cell cultures. Fine control over the porosity and structure of a material ensures adequate cell adhesion and fit between the graft and the defect. Several recent tissue engineering studies have focused on the trachea, nose, and ear, as these structures are often damaged by congenital conditions, trauma, and malignancy. This article reviews the limitations of current reconstructive techniques and the new developments in additive manufacturing for tracheal, nasal, and auricular cartilages.

Surgery for nonlocalizing hyperparathyroidism in high volume center.

BACKGROUND: Patients with nonlocalizing hyperparathyroidism pose a significant challenge to surgeons when undergoing neck exploration for parathyroidectomy. METHODS: We evaluated 536 patients that had parathyroidectomy for primary hyperparathyroidism (PHPT) from 2005 to 2018 at a single tertiary academic center, and 155 (29%) had standard nonlocalizing preoperative imaging (negative ultrasound and sestamibi scans). RESULTS: There were a total of 102 (66%) non-ectopic single adenomas in the nonlocalizing group and 325 (85%) single adenomas in the localizing group. There was no significant difference (p = 0.09) in adenoma quadrant between localizing and nonlocalizing single adenomas, but the most common location in both groups was right inferior. Patients with nonlocalizing scans were more likely to have double adenomas (21% vs. 9%, p < 0.001), ectopic glands (10% vs. 5%, p = 0.052), and multi-gland disease (13% vs. 8%, p = 0.002). CONCLUSION: Nonlocalizing PHPT patients experienced similar cure and complication rates as localizing PHPT, but required more bilateral explorations and increased operative time.

Survey of Anesthesiologists on Topical Vasoconstrictors and Intravenous Tranexamic Acid for Endoscopic Sinus Surgery.

OBJECTIVES: Topical vasoconstrictors and intravenous tranexamic acid (IV TXA) are safe and efficacious to decrease bleeding and improve the surgical field during endoscopic sinus surgery (ESS). The purpose of this study was to investigate practice patterns, awareness of clinical evidence, and comfort levels among anesthesia providers regarding these hemostatic agents for ESS. METHODS: A total of 767 attending anesthesiologists, residents, and certified registered nurse anesthetists (CRNAs) at 5 United States academic centers were invited to participate in a survey regarding their experience with IV TXA and 3 topical vasoconstrictor medications (oxymetazoline, epinephrine, and cocaine) during ESS. RESULTS: 330 (47%) anesthesia providers responded to the electronic survey. 113 (97%) residents, 92 (83%) CRNAs, and 52 (68%) attendings managed 5 or fewer ESS cases per month. Two-thirds of providers had not reviewed efficacy or safety literature for these hemostatic agents. Oxymetazoline was perceived safest, followed by epinephrine, IV TXA, and cocaine. Respondents considered potential side effects over surgical field visibility when selecting agents. The majority of providers had no formal training on these agents for ESS, but indicated interest in educational opportunities. CONCLUSION: Many anesthesia providers are unfamiliar with safety and efficacy literature regarding agents used to improve hemostasis for ESS, highlighting a need for development of relevant educational resources. Rhinologic surgeons have an opportunity to communicate with anesthesia colleagues on the use of hemostatic agents to improve the surgical field during ESS.