CT-guided microcoil localization of pulmonary nodules: the effect of the position of microcoil proximal end on the incidence of microcoil dislocation

Objectives: To evaluate the effect of the position of microcoil proximal end on the incidence of microcoil dislocation during CT-guided microcoil localization of pulmonary nodules (PNs). Methods: This retrospective study included all patients with PNs who received CT-guided microcoil localization before video-assisted thoracoscopic urgery (VATS) resection from June 2016 to December 2019 in our institution. The microcoil distal end was less than 1 cm away from the nodule, and the microcoil proximal end was in the pleural cavity (the pleural cavity group) or chest wall (the chest wall group). The length of microcoil outside the pleura was measured and divided into less than 0.5 cm (group A), 0.5 to 2 cm (group B) and more than 2 cm (group C). Microcoil dislocation was defined as complete retraction into the lung (type I) or complete withdrawal from the lung (type II). The rate of microcoil dislocation between different groups was compared. Results: A total of 519 consecutive patients with 571 PNs were included in this study. According to the position of microcoils proximal end on post-marking CT, there were 95 microcoils in the pleural cavity group and 476 in the chest wall group. The number of microcoils in group A, B, and C were 67, 448 and 56, respectively. VATS showed dislocation of 42 microcoils, of which 30 were type II and 12 were type I. There was no statistical difference in the rate of microcoil dislocation between the pleural cavity group and the chest wall group (6.3% vs 7.6%, x2 = 0.18, p = 0.433). The difference in the rate of microcoil dislocation among group A, B, and C was statistically significant (11.9%, 5.8%, and 14.3% for group A, B, and C, respectively, x2 = 7.60, p = 0.008). In group A, 75% (6/8) of dislocations were type I, while all eight dislocations were type II in group C. Conclusions: During CT-guided microcoil localization of PNs, placing the microcoil proximal end in the pleura cavity or chest wall had no significant effect on the incidence of microcoil dislocation. The length of microcoil outside the pleura should be 0.5 to 2 cm to reduce the rate of microcoil dislocation. Advances in knowledge: : CT-guided microcoil localization can effectively guide VATS to resect invisible and impalpable PNs. Microcoil dislocation is the main cause of localization failure. The length of microcoil outside the pleura is significantly correlated with the rate and type of microcoil dislocation. Placing the microcoil proximal end in the pleura cavity or chest wall has no significant effect on the rate of microcoil dislocation.

Cuspal deflection caused by dental composite polymerization shrinkage analyzed by digital holography

Background/Aim. The objective of this study was to measure tooth cusps deflection caused by polymerization shrinkage of a resin-based dental material (RDM), in real-time using digital holographic interferometry (DHI), in two groups of cavities restored with and without an additional wall. Simultaneously, internal tooth mechanical behavior was monitored. Methods. Standardized three class I cavities were prepared on third molar teeth. The teeth were cut in two halves in the longitudinal plane, obtaining six samples for the study (now with class II cavities), divided into two groups (group G1 - with the additional wall, group G2 - without it) and mounted in aluminum blocks. The cavities were filled with the RDM, cured with a light emitting diode (LED) for 40 s from the occlusal direction, and monitored during the curing and post-curing period using DHI. Data were analyzed using student's t-test for independent samples and Anderson-Darling test, with an alpha level of 0.05. Results. At the end of the examined period, the samples from group G1 showed significantly increased tooth cusps deflection (t (10) = 4.7; p = 0.001) compared to samples from group G2. Conclusion. Within the limitations of this study, it was concluded that the presence of the additional wall simulating a dental matrix-band, influenced increased and prolonged tooth cusps deflection during the examined RDM polymerization shrinkage.

The classification of symmetry protected topological phases of one-dimensional fermion systems

We introduce an index for symmetry-protected topological (SPT) phases of infinite fermionic chains with an on-site symmetry given by a finite group G. This index takes values in $\mathbb {Z}_2 \times H^1(G,\mathbb {Z}_2) \times H^2(G, U(1)_{\mathfrak {p}})$ with a generalised Wall group law under stacking. We show that this index is an invariant of the classification of SPT phases. When the ground state is translation invariant and has reduced density matrices with uniformly bounded rank on finite intervals, we derive a fermionic matrix product representative of this state with on-site symmetry.

THE REAL GRADED BRAUER GROUP

We introduce a version of the Brauer–Wall group for Real vector bundles of algebras (in the sense of Atiyah) and compare it to the topological analogue of the Witt group. For varieties over the reals, these invariants capture the topological parts of the Brauer–Wall and Witt groups.

P6552Is it possible to recognize free-wall implantation of leadless pacemakers from an ECG?

Background Leadless pacemaker (Micra, Medtronic, US) is a effective treatment for bradycardia and eliminates any malfunctions related to intravenous leads. However, some cases exhibit pericardial effusion, presumably associated to device implantation to right ventricular free-wall. Objectives The present study was carried out to find ECG features during ventricular pacing by Micra, which enabled to distinguish free-wall implantation from septal implantation without imaging modalities. Methods Consecutive 21 patients who received implantation of Micra in our facility were enrolled. Location of device in the right ventricle was evaluated using echocardiography or computed tomography in order to determine whether the device was implanted on the septum or the freewall. The difference of 12-lead ECG during ventricular pacing from Micra were analyzed between the septum group and the free wall group. Results According to the imaging investigation, body of Micra was clearly identifiable in 17 patients. The locations of device were classified into septum in 11 patients, free-wall in 4 patients, and indeterminate but apex in 2 patients. Further analysis regarding ECG was performed exclusively between the septum group and the free-wall group. In lead V1, peak deflection index (PDI) was significantly larger in free-wall group than septum group (0.64±0.06 vs. 0.45±0.10, P=0.005), whereas there was no difference of QRS duration, transitional zone and QRS pattern. PDI of V1 and Location of LPM Conclusion PDI of V1 could be useful to predict implantation of Micra to free-wall and may potentially stratify the risk of postprocedural pericardial effusion.

Primary Arterial Switch Operation for Late Referral of Transposition of the Great Arteries with Intact Ventricular Septum in the Current Era: Do We Still Need a Rapid Two-Stage Operation?

Objective: We introduced primary arterial switch operation for the patient with transposition of great arteries and intact ventricular septum (TGA-IVS) who had more than 3.5 mm of posterior left ventricle (LV) wall thickness. Methods: Between January 2013 and June 2015, a total of 116 patients underwent arterial switch operation. Of the 116 patients, 26 with TGA-IVS underwent primary arterial switch operation at more than 30 days of age. Results: The age and body weight (mean ± SD) at the operation were 120.4 ± 93.8 days and 4.1 ±1.0 kg, respectively. There was no hospital mortality. The thickness of posterior LV wall (preoperation vs postoperation; mm) was 4.04 ± 0.71 versus 5.90 ± 1.3; P < .0001; interval: 11.8 ± 6.5 days. The left atrial pressure (mm Hg; postoperative day 0 vs 3) was 20.0 ± 3.2 versus 10.0 ± 2.0; P < .0001; and the maximum blood lactate level (mmol/dL) was 4.7 ± 1.4 versus 1.4 ± 0.3; P < .0001, which showed significant improvement in the postoperative course. All cases had delayed sternal closure. The patients who belonged to the thin LV posterior wall group (<4 mm [preoperative echo]: n = 13) had significantly longer ventilation time (days; 10.6 ± 4.8 vs 4.8 ± 1.7, P = .0039), and the intensive care unit stay (days) was 14 ± 9.2 versus 7.5 ± 3.5; P = .025, compared with thick LV wall group (≥4.0 mm: n = 13). Conclusions: The children older than 30 days with TGA-IVS can benefit from primary arterial switch operation with acceptable results under our indication. However, we need further investigation for LV function.