Feasibility of MRI for the evaluation of interosseous ligament vertical segment via subtalar arthroscopy correlation: comparison of 2D and 3D MR images

Background Interosseous ligament vertical segment (IOLV) and calcaneofibular ligament (CFL) have been reported to be important in stabilizing the subtalar joint. Unlike CFL, there is not much information regarding the comparison of MRI results with surgical evaluation of IOLV and the comparison between 2D and 3D MRI on IOLV evaluation. The feasibility of MRI in IOLV evaluation has yet to be reported. The purpose of this study was to evaluate the validity and reliability of MRI in IOLV tear detection via correlation with arthroscopic results. We also compared the diagnostic performance of 2D and 3D MR images. Methods In this retrospective study, 52 patients who underwent subtalar arthroscopy after ankle MRI were enrolled. Arthroscopic results confirmed IOLV tear in 25 cases and intact IOLV in 27 cases. Two radiologists independently evaluated the IOLV tears using only conventional 2D images, followed by isotropic 3D images, and comparison with arthroscopic results. Results Only the 2D sequences interpreted by two readers showed a sensitivity of 64.0–96.0%, a specificity of 29.6–44.4%, a positive predictive value of 51.6–56.4%, and a negative predictive value of 57.1–88.9%. Addition of isotropic 3D sequences changed the sensitivity to 60.0–80.0%, specificity to 63.0–77.8%, positive predictive value to 64.3–76.9%, and negative predictive value to 66.7–80.8%. The overall diagnostic performance of isotropic 3D sequences (AUC values: 0.679–0.816) was higher than that of 2D sequences (AUC values: 0.568–0.647). Inter-observer and intra-observer agreement between the two readers was moderate-to-good for both 2D and 3D sequences. The diagnostic accuracy in 19 patients with tarsal sinus fat obliteration tended to increase from 26.3–42.1% to 57.9–73.7% with isotropic 3D sequences compared with 2D sequences. Conclusions Isotropic 3D MRI was feasible for the assessment of IOLV tear prior to subtalar arthroscopy. Additional 3D sequences showed higher diagnostic accuracy compared with conventional 2D sequences in IOLV evaluation. Isotropic 3D sequences may be more valuable in detecting IOLV tear in case of tarsal sinus fat obliteration.

Gross and Micro-Anatomical Study of the Cavernous Segment of the Abducens Nerve and Its Relationships to Internal Carotid Plexus: Application to Skull Base Surgery

The present study aims to provide detailed observations on the cavernous segment of the abducens nerve (AN), emphasizing anatomical variations and the relationships between the nerve and the internal carotid plexus. A total of 60 sides underwent gross-anatomical study. Five specimens of the AN were stained using Sihler’s method. An additional five specimens were subjected to histological examination. Four types of AN course were observed: a single nerve along its entire course, duplication of the nerve, division into separate rootlets at the point of contact with the cavernous part of the internal carotid artery (ICA), and early-branching before entering the orbit. Due to the relationships between the ICA and internal carotid plexus, the cavernous segment of the AN can be subdivided into a carotid portion located at the point of contact with the posterior vertical segment of the cavernous ICA and a prefissural portion. The carotid portion of the cavernous AN segment is a place of angulation, where the nerve always directly adheres to the ICA. The prefissural portion of the AN, in turn, is the primary site of fiber exchange between the internal carotid plexus and either the AN or the lateral wall of the cavernous sinus.

The Thickness of the facial Nerve Sheath Consistently Varies by Region in Its Intra-Tympanic Course on Cadaveric Study

Objectives: Iatrogenic removal of intra-temporal disease processes, such as cholesteatoma and keratosis obturans, can be challenging when the facial nerve (FN) is involved. Despite this concern about possible FN injury during these procedures, our clinical observation has been that the diseased growth can be cleaned quite easily from the vertical FN epineurium. Therefore, we designed a cadaveric protocol to measure thickness of the FN sheath (epineurium) in horizontal, second genu and vertical FN segments and to correlate these measurements with surgical management of FN disorders. Methods: Fifty non-fixated (wet) cadaveric temporal bones were dissected over 1 year’s time. The intra-temporal FN sheath epineurium was harvested from the mid-horizontal, second genu, and mid-vertical segments. Using a digital micrometric technique, the thickness of each sample was measured. Data analysis was performed using student’s two-tailed, dependent t-test. Results: Epineurial nerve sheath thickness was the least in the horizontal segment (mean 0.9 mm, range 0.040-0.140 mm), greater at the second genu (mean 0.19 mm, range 0.010-0.280 mm), and greatest in the vertical segment (mean 0.29 mm, range 0.170-0.570 mm). These differences were statistically significant. Conclusion: In cases of cholesteatoma and keratosis obturans involving the vertical FN, the disease process can be separated from the FN sheath because of the sheath thickness in this region. Disease in the horizontal segment involves a thinner sheath and separating the disease process from the nerve is more difficult in this area.

The Impact of the 2019-nCoV on the Oral Medical Industry and the Corresponding Strategies

The outbreak of new crown pneumonia has had a great impact on Chinese enterprises. As a highly market-oriented medical vertical segment industry, oral institutions have been impacted and affected unprecedentedly in this epidemic. Through the analysis of the specific impact on the stomatology industry, this paper puts forward and its countermeasures, and provides suggestions for enterprises to eliminate the negative impact of the epidemic on enterprises to the greatest extent and promote the benign development of enterprises.

A CANOPY FROM THE PORTUGUESE MEDIEVAL MONASTERY OF BATALHA: A SINGULAR EXAMPLE OF MICRO-ARCHITECTURE IN THE CLOISTERS COLLECTION

The MET Cloisters acquired a peculiar architectural canopy in 2016 that belonged to the main portal of the medieval monastery of Santa Maria da Vitória in the Portuguese village of Batalha. This piece, now in New York, surmounted one of the twelve statues of the Apostles. In the 19th century, during restoration works, the portal was altered from its initial dimension and many of its original sculptural elements were replaced by copies. This research note intends to trace the current location of all the original elements, in both public and private collections, as well as their path in the art market. It also analyzes how this canopy represents a unique example of micro-architecture, relating its composition to the monastery’s architecture. The canopy seems to allude to the dual function and meaning of the Portuguese medieval monastery: the divine temple is represented by the five small buildings and their tile-roofs, as the church’s chevet with five radiating chapels; and royal funerary place as represented by the vertical segment, a sectioned octagonal volume evoking King John’s funeral chapel. In its simplicity and micro-scale, this canopy displays remarkable artistic quality, constituting an excellent example of the fourteenth-century production led by the master Huguet in the Portuguese construction site of Batalha.

The medial wall of the cavernous sinus. Part 1: Surgical anatomy, ligaments, and surgical technique for its mobilization and/or resection

OBJECTIVEThe medial wall of the cavernous sinus (CS) is often invaded by pituitary adenomas. Surgical mobilization and/or removal of the medial wall remains a challenge.METHODSEndoscopic endonasal dissection was performed in 20 human cadaver heads. The configuration of the medial wall, its relationship to the internal carotid artery (ICA), and the ligamentous connections in between them were investigated in 40 CSs.RESULTSThe medial wall of the CS was confirmed to be an intact single layer of dura that is distinct from the capsule of the pituitary gland and the periosteal layer that forms the anterior wall of the CS. In 32.5% of hemispheres, the medial wall was indented by and/or well adhered to the cavernous ICA. The authors identified multiple ligamentous fibers that anchored the medial wall to other walls of the CS and/or to specific ICA segments. These parasellar ligaments were classified into 4 groups: 1) caroticoclinoid ligament, spanning from the medial wall and the middle clinoid toward the clinoid ICA segment and anterior clinoid process; 2) superior parasellar ligament, connecting the medial wall to the horizontal cavernous ICA and/or lateral wall of the CS; 3) inferior parasellar ligament, bridging the medial wall to the anterior wall of the CS or anterior surface of the short vertical segment of the cavernous ICA; and 4) posterior parasellar ligament, which anchors the medial wall to the short vertical segment of the cavernous ICA and/or the posterior carotid sulcus. The caroticoclinoid ligament and inferior parasellar ligament were present in most CSs (97.7% and 95%, respectively), while the superior and posterior parasellar ligaments were identified in approximately half of the CSs (57.5% and 45%, respectively). The caroticoclinoid ligament was the strongest and largest ligament, and it was typically assembled as a group of ligaments with a fan-like arrangement. The inferior parasellar ligament was the first to be encountered after opening the anterior wall of the CS during an interdural transcavernous approach.CONCLUSIONSThe authors introduce a classification of the parasellar ligaments and their role in anchoring the medial wall of the CS. These ligaments should be identified and transected to safely mobilize the medial wall away from the cavernous ICA during a transcavernous approach and for safe and complete resection of adenomas that selectively invade the medial wall.