Moon MH, et al. J Korean Med Sci. 2010 May;25(5):658-662. http://dx.doi.org/10.3346/jkms.2010.25.5.658

Irreversible electroporation (IRE) is a tissue ablation method, uses short high electric pulses and results in cell death in target tissue by irreversibly permeabilizing the cell membrane. Potato is commonly used as a tissue model for electroporation experiments. The blackened area that forms 12 h after electric pulsing is regarded as an IRE-ablated area caused by melanin accumulation. Here, the 2,3,5-triphenyltetrazolium chloride (TTC) was used as a dye to assess the IRE-ablated area 3 h after potato model ablation. Comparison between the blackened area and TTC-unstained white area in various voltage conditions showed that TTC staining well delineated the IRE-ablated area. Moreover, whether the ablated area was consistent over time and at different staining times was investigated. In addition, the presumed reversible electroporation (RE) area was formed surrounding the IRE-ablated area. Overall, TTC staining can provide a more rapid and accurate electroporated area evaluation.

Differences in post-Nuss procedure pulmonary function based on the pectus excavatum subtype have not been investigated in adolescents. We evaluated differences in pulmonary function before and after the Nuss procedure according to preoperative morphology. We performed a retrospective review of eighteen male patients who had undergone the Nuss procedures. There were nine patients each with symmetric and asymmetric morphology. Patients were younger than 18 years and had no history of respiratory diseases. Pulmonary function was assessed 2 weeks before and 4–6 months after the surgery. Preoperative and postoperative pulmonary function data were compared between the symmetric and asymmetric types. The paired t-test was used to compare the differences within each group and an analysis of covariance (ANCOVA) was used to access intergroup differences. There were no significant demographic differences between patients with symmetric and asymmetric subtypes. Patients with the asymmetric type had a lower preoperative total lung capacity (TLC) (p = 0.018), vital capacity (VC) (p = 0.0308), and inspiratory capacity (IC) (p = 0.0373). In both types, the forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and VC were all significantly decreased postoperatively compared to baseline (all, p < 0.01). The asymmetric type showed further reductions in peak expiratory flow (PEF) (p = 0.0391) and IC (p = 0.0084) postoperatively. The residual volume (RV) (p = 0.0092) and RV/TLC ratio (p = 0.0025) increased significantly in the asymmetric type, but only the postoperative PEF values differed significantly between the two types (p = 0.0151). The asymmetric type had poorer preoperative lung volumes and poorer postoperative pulmonary function, with significantly lower PEF compared to the symmetric type cases. Preoperative and postoperative lung function needs more careful evaluation until pectus bar removal in the asymmetric type of pectus excavatum.

Bar displacement is one of the most common and serious complications after the Nuss procedure. However, measurements of and factors affecting bar displacement have not been reported. The objectives of this study were to develop a decision model to guide surgeons considering repeat treatment and to estimate optimal cut-off values to determine whether reoperation to correct bar displacement is warranted. From July 2011 to August 2013, ninety bars were inserted in 61 patients who underwent Nuss procedures for pectus excavatum. Group A did not need surgical intervention and Group B required reoperation for bar displacement. Bar position was measured as the distance from the posterior superior end of the sternal body to the upper border of the metal bar on lateral chest radiographs. The bar displacement index (BDI) was calculated using D0 - Dx / D0 x 100 (D0: bar position the day after surgery; Dx: minimal or maximal distance of bar position on the following postoperative days). The optimal cut-off values of BDI warranting reoperation were assessed on the basis of ROC curve analysis. Of the 61 patients, 32 had single bars inserted whereas 29 had parallel bars inserted. There was a significant difference in age (14.0 ± 7.5 vs. 23.3 ± 12.0, p = 0.0062), preoperative Haller index (HI) (4.0 ± 1.1 vs. 5.0 ± 1.0, p = 0.033), and postoperative HI (2.7 ± 0.4 vs. 3.2 ± 0.5 p = 0.006) between the two groups. The optimal cut-off value of BDI was 8.7. We developed a BDI model for surgeons considering performing reoperation after Nuss procedure. The optimal cut-off value of BDI was 8.7. This model may help surgeons to decide objectively whether corrective surgery should be performed. The main factors affecting the relationship between bar displacement and reoperation were age and preoperative HI.

Pulmonary nodules may require thoracoscopic resection in cases where percutaneous needle aspiration (PCNA) is non-diagnostic or not technically feasible. We developed a new protocol to localize pulmonary nodules concomitantly with PCNA. We retrospectively reviewed the use of concomitant PCNA and preoperative localization under computed tomography (CT) guidance. From Jan 2006 to Dec 2013, we performed PCNA and localization concomitantly on 34 pulmonary nodules (in 33 patients) using self-made, platinum microcoils. Patients in which PCNA results were less likely to be non-diagnostic and who were anticipating thoracoscopy were eligible to participate in this study. The CT-guided PCNA biopsy and microcoil localization was performed on the day of the VATS in the CT suite. The PCNA specimen was sent to the pathologist for frozen section pathology. If diagnosis of the lesion was not confirmed by PCNA or was primary lung cancer, the patient was moved to the operating room for VATS surgery. Between Jan 2006 and Dec 2013, concomitant PCNA and localization were successfully performed on 34 pulmonary nodules from 33 patients (one patient had two nodules). Of the 34 nodules, seven were diagnosed pathologically using PCNA, and 27 nodules that could not be diagnosed by PCNA were excised by thoracoscopic resection without additional procedures or time because of concomitant localization. There were no deaths or significant morbidities. Minor complications included three incidents of lung hemorrhage and five of pneumothorax (two required closed thoracostomy drainage). Of 34 nodules in which both PCNA and localization were used, thoracoscopic resections were performed on 33, lobectomies were performed concomitantly with thoracoscopic resection on 11. Intraoperative fluoroscopy was used to detect 33 of 34 nodules localized using the platinum microcoil (97.06 %) or to guide stapling during thoracoscopic resection. The advantages of this technique are 1) there is no need for further localization during thoracoscopy even in cases of unsuccessful PCNA, 2) it is more effective with respect to both cost and time, and 3) it provides greater patient comfort.