Tibiofibular Space Widening Assessment With a Ball-Tipped Probe in a Syndesmosis Injury Model.

Assessment of syndesmotic instability is not precise with existing evaluation methods. This study was conducted to investigate the use of a ball-tipped probe under arthroscopy for quantitative assessment of tibiofibular space widening in a syndesmosis injury model. The test specimens were 5 uninjured ankles from Thiel-fixed cadavers of 2 male subjects and 3 female subjects of mean age of 82.4 years at death. The ball-tipped probe consisted of a metal probe having a ball at each end with diameters ranging from of 1.5 mm to 5.0 mm, in increments of 0.5 mm. The tibiofibular joint was observed arthroscopically as the largest-diameter ball probe as possible was inserted into its anterior third, middle, or posterior third portion with the ankle in natural plantarflexion or under external rotational stress. These measurements were performed for the uninjured ankle and then performed following Bassett's ligament sectioning, anterior inferior tibiofibular ligament sectioning, interosseous membrane distal 15 cm sectioning, or deltoid ligament, and posterior inferior tibiofibular ligament sectioning, with the sections added in this sequence and each followed by a similar assessment. The results of quantitative assessment of tibiofibular space widening with the ball-tipped probe in the syndesmosis injury model under arthroscopy were that the maximum possible diameter of ball probe that could be inserted was 1.5 to 2.0 mm in the uninjured state, 3.0 to 3.5 mm in the sectioned anterior inferior tibiofibular ligament model, and 5.0 mm in the severe-state model. The ball probe can serve as an effective tool for quantitative assessment of the intraoperative instability in cases of syndesmosis injury.

The value of the black fiber sign on T1-weighted images for predicting stability of desmoid fibromatosis managed conservatively.

OBJECTIVES: It is challenging to know at the first which patients with desmoid fibromatosis (DF) are better suited to conservative or aggressive treatment. To investigate whether the low signal intensity bundles on T1- or T2-weighted images (WI), termed the "black fiber sign (BFS)," can predict non-progressive behavior in the conservative approach. METHODS: This retrospective study included 59 patients with primary DF managed with wait-and-see approach from 2005 to 2018 and serial MR images were analyzed. Three observers blinded to the patient information verified the presence or absence of BFS on baseline T1 or T2WI. The likelihood of progression-free survival (PFS) after ascertaining the presence or absence of the BFS was estimated using the Kaplan-Meier method and analyzed with the log-rank test. RESULTS: PFS was significantly higher in cases with BFS than without BFS on T1WI (p < 0.01), but there was no significant difference in PFS between cases with and without BFS on T2WI. Multivariable Cox proportional hazards analysis revealed that the absence of BFS on T1WI was a high-risk factor for progression (hazard ratio, 14.9; p < 0.01). Drastic tumor regression was apparent with significantly increased low-signal area in cases with BFS on T1WI. Intra- and interobserver reliabilities of BFS on T1WI were in almost-perfect agreement (κ > 0.8). CONCLUSION: Our retrospective observational data support that presence of BFS in baseline MRI may be a predictor for progression-free survival of DF. BFS on T1WI is easily identifiable and can be utilized clinically in patients with DF. KEY POINTS: • We proposed a new imaging marker for prediction of desmoid fibromatosis progression. • The absence of black fiber sign predicted a high risk of disease progression.

Tibial Plafond Attachment of the Posterior-Inferior Tibiofibular Ligament: A Cadaveric Study.

BACKGROUND: Some recent studies have reported the role of the posterior malleolus as an attachment of the posterior-inferior tibiofibular ligament (PITFL) and suggested that even a small fragment should be fixed. However, there are few anatomic studies of the tibial plafond attachment of the PITFL. METHODS: Seven Thiel-embalmed ankles were obtained. The margin of the distal tibial joint surface and the attachments of the superficial fiber of the PITFL (sPITFL) and the deep fiber (dPITFL) were identified. In the frontal view, the percentages of the attachments of the sPITFL and dPITFL of the mediolateral dimension of the posterior tibial plafond were measured. In the lateral view, the line that started from the proximal margin of the attachment of the sPITFL and parallel to the tibial axis was drawn, and the distance between that line and the posterior edge of the joint surface was measured (AP distance of the sPITFL). Then, the percentage of the AP distance of the sPITFL of the joint surface in the anteroposterior dimension of the tibial plafond was measured. RESULTS: In the frontal view, the mediolateral distance of the attachment of the sPITFL was 5.0 mm, and that of the dPITFL was 19.5 mm. The percentage of the attachment of the sPITFL on the tibial plafond was 20.6%, and that of the dPITFL was 78.2%. In the lateral view, the average AP distance of the sPITFL was 0.5 mm, and the percentage in the anteroposterior dimension of the tibial plafond was 1.7%. CONCLUSION: The PITFL was attached to less than 10% of the anteroposterior dimension of the tibial plafond in most ankles. Conversely, the PITFL attached widely in the mediolateral dimension. CLINICAL RELEVANCE: This study suggests that the size of the posterior malleolar fragment in the mediolateral dimension could help estimate how much of the PITFL attaches to the fragment which may have implications for ankle stability.

Mouse zona pellucida dynamically changes its elasticity during oocyte maturation, fertilization and early embryo development.

A change in the elasticity of mouse zona pellucida was quantitatively evaluated during oocyte maturation, fertilization and early embryo development. Young's modulus of zona pellucida of germinal vesicle (GV), metaphase-II (MII), pronuclear (PN), 2cell, 4cell, 8cell, morulae (M) and early blastocyst (EB) stages was measured using a micro tactile sensor (MTS) and a chamber exclusively designed for the measurement. The MTS has very high sensitivity and a deformation of only 5 microm was sufficient to calculate the Young's modulus and the oocyte/embryo maintained its original spherical shape during the measurement. The Young's modulus of GV, MII, PN, 2cell, 4cell, 8cell, M and EB was 22.8+/-10.4 kPa (n=30), 8.26+/-5.22 kPa (n=74), 22.3+/-10.5 kPa (n=66), 13.8+/-3.54 kPa (n=41), 12.6+/-3.34 kPa (n=19), 5.97+/-4.97 kPa (n=6), 1.88+/-1.34 kPa (n=8) and 3.39+/-1.86 kPa (n=4), respectively. Experimental results clearly demonstrated that the mouse zona pellucida hardened following fertilization. Interestingly, once the zona pellucida hardened at the PN stage, it gradually softened as the embryo developed (i.e. it was found that the zona hardening is a transient phenomenon). Furthermore, the zona pellucida of the GV oocyte was as hard as that of the PN embryo and became soft as it matured to the MII stage. In addition, the safety of the MTS measurement for oocytes and embryos was discussed both theoretically and experimentally.

[Serum and urinary inorganic fluoride concentrations with renal and hepatic functions after repeated sevoflurane anesthesia].

The purpose of this study is to examine changes in serum and urinary inorganic fluoride (F) concentrations with their effects on renal and hepatic functions after repeated sevoflurane anesthesia with relatively short time interval. Eight patients received sevoflurane anesthesia twice within 7 days for gynecological surgery. Serum and urine F levels before induction, 0.5 and 1 hour after induction, and 0.5 hour after anesthesia were compared between first and second anesthesia. There were no significant differences in serum and urine F concentrations at the same point between first and second anesthesia. Two obese patients exhibited peak concentrations greater than 50 mumol.l-1 of F. Laboratory findings of renal function remained stable throughout 2 operations, whereas hepatic function deteriorated in the two obese patients after the first anesthesia, and resolved within 14 days after the second anesthesia. In conclusion, it is suggested that the second exposure to sevoflurane within 7 day interval does not alter the sevoflurane metabolism. However, obesity may contribute to a rise in serum inorganic fluoride after repeated sevoflurane anesthesia.