Kazuto Ohtaka

Dr. Kazuto Ohtaka


Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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6 January 2014 in Journal of Cardiothoracic Surgery
Verified
Journal Article
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KOKazuto Ohtaka
Kazuto Ohtaka
YHYasuhiro Hida
Yasuhiro Hida
KKKichizo Kaga
Kichizo Kaga
YTYasuhiro Takahashi
Yasuhiro Takahashi
HKHiroshi Kawase
Hiroshi Kawase
Yoshiro MatsuiYoshiro Matsui
Yoshiro Matsui
Thrombosis in the left upper pulmonary vein stump after left upper lobectomy is a very rare but important complication because it occurs in the systemic circulation system. We previously made the first ever report on the frequency and risk factors of thrombosis in the pulmonary vein stump after lobectomy. In this study, we conducted an investigation in a different hospital to determine whether this was a common complication. From 2008 to 2012, 151 patients who underwent lobectomy and following enhanced CT within 2 years after the operation were studied. Postoperative contrast-enhanced CT imaging was retrospectively checked. We found thrombosis in the pulmonary vein stump in 5 of the 151 patients (3.3%). All 5 patients underwent left upper lobectomy (17.9% of the patients who underwent left upper lobectomy). These 5 patients did not have infarction of any vital organ. The thrombus was disappeared several months later on contrast-enhanced CT in 3 patients and followed in 2 patients. On univariate analysis, there was a significant difference only in the operative procedure (p < 0.001). Thrombosis in the pulmonary vein stump occurred with high frequency in patients who underwent left upper lobectomy. Because the frequency of thrombosis in this study was the same as in our previous report, this might be a common complication.

18 September 2014 in Journal of Cardiothoracic Surgery
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Journal Article
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KOKazuto Ohtaka
Kazuto Ohtaka
YTYasuhiro Takahashi
Yasuhiro Takahashi
SUSatoko Uemura
Satoko Uemura
YSYasuhito Shoji
Yasuhito Shoji
SHSatoshi Hayama
Satoshi Hayama
Yoshiro MatsuiYoshiro Matsui
Yoshiro Matsui
We previously reported that arterial infarction of vital organs after lobectomy might occur only after left upper lobectomy and be caused by thrombosis in the left superior pulmonary vein stump. We hypothesized that changes in blood flow, such as blood stasis and disturbed stagnant flow, in the left superior pulmonary vein stump cause thrombosis, and this was evaluated by intraoperative ultrasonography. From July 2013 to April 2014, 24 patients underwent lobectomy in the Steel Memorial Muroran Hospital. During the procedure, an ultrasound probe was placed at the pulmonary vein stump and the velocity in the stump was recorded with pulse Doppler mode. The peak velocity and the presence of spontaneous echo contrast in the stump were evaluated. After the operation, the patients underwent contrast-enhanced CT within 3 months. The operative procedures were seven left upper lobectomies, four left lower lobectomies, seven right upper lobectomies, and six right lower lobectomies. Blood flow was significantly slower in the left superior pulmonary vein stump than in the right pulmonary vein stumps. However, that was not significantly slower than that in the left inferior pulmonary vein stump. Spontaneous echo contrast in the pulmonary vein stump was seen in three patients who underwent left upper lobectomy. Of the three patients with spontaneous echo contrast, two patients developed thrombosis in the left superior vein stump within 3 months after the operation. There was no patient who developed arterial infarction. In patients who underwent left upper lobectomy, intraoperative ultrasonography to evaluate blood flow and the presence of spontaneous echo contrast in the left superior pulmonary vein stump may be useful to predict thrombosis that may cause arterial infarction.

20 June 2014 in Journal of Cardiothoracic Surgery
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Journal Article
Open access
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KOKazuto Ohtaka
Kazuto Ohtaka
YTYasuhiro Takahashi
Yasuhiro Takahashi
KKKichizo Kaga
Kichizo Kaga
NSNaoto Senmaru
Naoto Senmaru
YKYoshihisa Kotani
Yoshihisa Kotani
Yoshiro MatsuiYoshiro Matsui
Yoshiro Matsui
The O-arm is an intraoperative imaging device that can provide computed tomography images. Surgery for small lung tumors was performed based on intraoperative computed tomography images obtained using the O-arm. This study evaluated the usefulness of the O-arm in thoracic surgery. From July 2013 to November 2013, 10 patients with small lung nodules or ground glass nodules underwent video-assisted thoracoscopic surgery using the O-arm. A needle was placed on the visceral pleura near the nodules. After the lung was re-expanded, intraoperative computed tomography was performed using the O-arm. Then, the positional relationship between the needle marking and the tumor was recognized based on the intraoperative computed tomography images, and lung resection was performed. In 9 patients, the tumor could be seen on intraoperative computed tomography images using the O-arm. In 1 patient with a ground glass nodule, the lesion could not be seen, but its location could be inferred by comparison between preoperative and intraoperative computed tomography images. In only 1 patient with a ground glass nodule, a pathological complete resection was not performed. There were no complications related to the use of the O-arm. The O-arm may be an additional tool to facilitate intraoperative localization and surgical resection of non-palpable lung lesions.

24 April 2013 in Journal of Cardiothoracic Surgery
Verified
Journal Article
Open access
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KOKazuto Ohtaka
Kazuto Ohtaka
YHYasuhiro Hida
Yasuhiro Hida
KKKichizo Kaga
Kichizo Kaga
TKTatsuya Kato
Tatsuya Kato
JMJun Muto
Jun Muto
Yoshiro MatsuiYoshiro Matsui
Yoshiro Matsui
Background: Lung tumors showing ground-glass opacities on high-resolution computed tomography indicate the presence of inflammation, atypical adenomatous hyperplasia, or localized bronchioloalveolar carcinoma. We adopted a two-staged video-assisted thoracoscopic lobectomy strategy involving completion lobectomy for localized bronchioloalveolar carcinoma with an invasive component according to postoperative pathological examination by permanent section after partial resection. Methods: Forty-one patients with undiagnosed small peripheral ground-glass opacity lesions underwent partial resection from 2001 to 2007 in Hokkaido University Hospital. Localized bronchioloalveolar carcinoma was classified according to the Noguchi classification for adenocarcinoma. Malignant lesions other than Noguchi types A and B were considered for completion lobectomy and systemic mediastinal lymphadenectomy. Perioperative data of completion video-assisted thoracoscopic lobectomies were compared with data of 67 upfront video-assisted thoracoscopic lobectomies for clinical stage IA adenocarcinoma performed during the same period. Results: Postoperative pathological examination revealed 35 malignant and 6 non-malignant diseases. Histologically, all of the malignant diseases were adenocarcinomas of Noguchi type A (n = 7), B (n = 9), C (n = 18), and F (n = 1). Eleven of 19 patients (58%) with Noguchi type C or F underwent two-staged video-assisted thoracoscopic lobectomy. Three patients refused a second surgery. There was no cancer recurrence. The two-staged lobectomy group had a significantly longer operative time and more blood loss than the upfront lobectomy group. There was no surgical mortality or cancer recurrence. Conclusions: Two-staged lobectomy for undiagnosed small peripheral ground-glass opacity lesions showed satisfactory oncological results. However, low compliance for and invasiveness of the second surgery are concerns associated with this strategy.

23 April 2019 in Surgical Case Reports
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Journal Article
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KOKazuto Ohtaka
Kazuto Ohtaka
NINozomu Iwashiro
Nozomu Iwashiro
KWKazunori Watanabe
Kazunori Watanabe
TMTomoko Mizota
Tomoko Mizota
RTRyo Takahashi
Ryo Takahashi
Yoshiro MatsuiYoshiro Matsui
Yoshiro Matsui
Since a displaced bronchus related to the left upper lobe is an uncommon anatomical anomaly, it has a risk of being accidentally resected during left upper lobe resection unless they are identified preoperatively. A case of video-assisted thoracic surgery (VATS) segmentectomy that was safely performed under preoperative identification of a displaced subsegmental bronchus and anomalous pulmonary vessels is presented. A 48-year-old woman visited our hospital because of an abnormal shadow on a radiograph on a health check. The chest computed tomography (CT) showed a multicystic mass with a diameter of 35 mm on dorsal interlobar parenchyma between the S1+2 and S6 segments in the left lung. The three-dimensional (3D) CT with multiplanar reconstruction showed that B1+2b+c passed to the dorsal side of the left main pulmonary artery (PA), which was considered a displaced bronchus. The branch of A6 arose from the left main PA at the level of the branches of A3 and A1+2, more proximal than the normal anatomy, and passed to the dorsal side of a displaced B1+2b+c. The branch of V1+2 passed between B6 and the bronchus to the basal segment and joined V6 at the dorsal side of the pulmonary hilum. Intraoperative findings of the anatomy of the bronchi and pulmonary vessels were exactly the same as the preoperative 3D CT findings, so segmentectomy of S1+2b+c and S6 by VATS was performed safely. Then there were accessory fissures between S1+2 and S3 and between S6 and the basal segment. The pathological diagnosis was a left lung abscess. A preoperative 3D CT may be helpful for identifying anatomical anomalies. An anatomical anomaly should be suspected if accessory fissure is found during surgery.

28 October 2016 in Clinical Case Reports
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Journal Article
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KOKazuto Ohtaka
Kazuto Ohtaka
RHRyunosuke Hase
Ryunosuke Hase
RCRyohei Chiba
Ryohei Chiba
MMMamoru Miyasaka
Mamoru Miyasaka
SSShoki Sato
Shoki Sato
YMYoshiro Matsui
Yoshiro Matsui
Splenic injury is one of the most critical complications of chest tube insertion and often requires invasive emergency management. However, noninvasive management such as delayed removal of the malpositioned tube may be considered for a stable patient without severe adverse event.