Reappraisal of intergender differences in the urethral striated sphincter explains why a completely circular arrangement is difficult in females: a histological study using human fetuses / 대한해부학회지

To investigate why the development of a completely circular striated sphincter is so rare, we examined histological sections of 11 female and 11 male mid-term human fetuses. In male fetuses, the striated muscle initially extended in the frontal, rather than in the horizontal plane. However, a knee-like portion was absent in the female fetal urethra because, on the inferior side of the vaginal end, a wide groove for the future vestibule opened inferiorly. Accordingly, it was difficult for the developing striated muscle to surround the groove, even though there was not a great difference in width or thickness between the female vestibule and the male urethra. The development of a completely circular striated sphincter seems to be impossible in females because of interruption of the frontal plane by the groove-like vestibule. However, we cannot rule out the possibility that before descent of the vagina, the urethral striated muscle extends posteriorly.

Reappraisal of intergender differences in the urethral striated sphincter explains why a completely circular arrangement is difficult in females: a histological study using human fetuses / 대한해부학회지

To investigate why the development of a completely circular striated sphincter is so rare, we examined histological sections of 11 female and 11 male mid-term human fetuses. In male fetuses, the striated muscle initially extended in the frontal, rather than in the horizontal plane. However, a knee-like portion was absent in the female fetal urethra because, on the inferior side of the vaginal end, a wide groove for the future vestibule opened inferiorly. Accordingly, it was difficult for the developing striated muscle to surround the groove, even though there was not a great difference in width or thickness between the female vestibule and the male urethra. The development of a completely circular striated sphincter seems to be impossible in females because of interruption of the frontal plane by the groove-like vestibule. However, we cannot rule out the possibility that before descent of the vagina, the urethral striated muscle extends posteriorly.

A New Index of Intraoperative Transit-Time Flow Evaluation in Coronary Artery Bypass Grafting / 日本心臓血管外科学会雑誌

It is essential to evaluate the quality of coronary artery bypass grafting (CABG) anastomosis in the operating room. Transit-time flow measurement has been increasingly used for this purpose, because it is less invasive, more reproducible, and less time consuming. The electrocardiogram-gated flow measurement has made it possible to identify the systolic flow (Qs) and diastolic flow (Qd) and to calculate a new index, diastolic filling index (DFI=100∫Qd/[∫|Qs|+∫|Qd|]) for graft flow analysis. In this study, we investigated the clinical significance of DFI, together with other indexes, including mean flow (Qm), pulsatility index (PI), % insufficiency (INSUF), and F0/H1, where F0 is a power of the fundamental frequency and H1 is a power of the first harmonic in spectral analysis by fast Fourier transformation of the flow curve. We examined the relationships of these intraoperative flow variables of the postoperative angiographic findings of 125 CABG grafts, including 58 <i>in-situ</i> internal thoracic arteries. There were significant differences between patent and non-patent grafts in all of the intraoperative flow parameters (Qm: 47.9±31.8ml/min vs 10.2±3.6ml/min, PI: 3.0±1.4 vs 9.6±2.4, INSUF: 3.3±4.2% vs 29.9±8.1%, F0/H1: 2.8±2.0 vs 0.6±0.2, DFI: 68.5±8.4% vs 38.2±17.2%). Our data suggested that a DFI value of more than 50% can be useful for surgeons to distinguish patent from non-patent grafts in the operating room, in combination with other parameters: Qm>15ml/min, PI<5, INSUF<15%, and F0/H1 ratio>1.0.

A Case of Thoracoabdominal Aneurysm with Retroperitoneal Fibrosis / 日本心臓血管外科学会雑誌

We describe our surgical experience of localized thoracoabdominal aneurysm in a 60-year-old woman with hypertension and hyperlipidemia. She was admitted for severe nausea associated with uremia. The initial CT scan revealed bilateral hydronephrosis, retroperitoneal fibrosis, inflammatory abdominal aneurysm, and localized thoracoabdominal aneurysm. To resolve the bilateral urinary tract obstruction, bilateral ureteral stents were inserted. After the renal function improved, the thoracoabdominal aneurysm was removed and replaced with an 18-mm woven-Dacron graft under partial cardiopulmonary bypass. The inflammation and fibrosis along the abdominal aorta did not extend to the thoracoabdominal aneurysm. Following the case presentation, we discussed the pathophysiologic aspects of this patient.

Experience of Coronary Artery Bypass Grafting on the Beating Heart with a Right Heart Bypass System / 日本心臓血管外科学会雑誌

Since November 1999 we have attempted to use a right heart bypass (RHB) system for beating heart coronary artery bypass grafting (CABG), which system produce better exposure of lateral and posterior wall of the heart and so enable us to facilitate bypass grafting to these branches. We report on our initial clinical experience with this system and the purpose of this study is to evaluate the efficacy of this system. To clarify the efficacy of the RHB system, we compared the intraoperative and postoperative clinical course, as well as outcome, between patients who underwent beating heart CABG with RHB and patients without RHB. Seventy-seven patients underwent beating heart CABG with RHB (RHB group) between November 1999 and December 2001. In the same period, 88 patients underwent beating heart CABG without RHB. Of these latter, 30 patients needed displacement of the beating heart in order to expose target coronary arteries (OPCAB group). Perioperative clinical parameters were compared between the groups. Patients in the RHB group received more grafts (2.4±0.6) than patients in the OPCAB group (2.0±0.2, <i>p</i>=0.002). There were no hospital deaths in either group. While displacing the beating heart, SvO₂ decreased and pulmonary artery pressure increased in both groups. Nevertheless, the value of SvO₂ was significantly higher in RHB group while displacing to expose the circumflex region (<i>p</i>=0.048) and the distal right coronary artery region (<i>p</i><0.01). The effect of elevation of pulmonary artery pressure in the RHB group was lower than that in the OPCAB group, but it was not statistically different. Water balance during operation was 2, 898±1, 019ml in the RHB group and the 2, 237±807ml in OPCAB group (<i>p</i>=0.002). Body temperature following operation was 36.0±0.8°C in the RHB group and 36.5±0.8°C in the OPCAB group (<i>p</i><0.01). However, no differences were found in postoperative blood loss, required transfusion, duration of mechanical ventilation, ICU stay and hospital stay. No patient had postoperative complications related to the RHB system. The introduction of the RHB enabled bypass grafting to posterior wall vessels with better exposure and under greater hemodynamic stability. Therefore we think it a very effective support system which enable multiple coronary revascularization on beating heart CABG.