Rectourethral fistula after external beam radiotherapy for prostate cancer in a patient with thromboangiitis obliterans: A case report.

INTRODUCTION: Thromboangiitis obliterans (TAO) is a rare disease of unknown cause that causes segmental vasculitis in peripheral blood vessels. It is uncertain whether its presence causes serious adverse events in patients receiving external beam radiotherapy. PATIENT CONCERNS: A 73-year-old Japanese man with prostate cancer underwent external beam radiotherapy. DIAGNOSIS: After completion of radiotherapy, fingertip pain occurred, leading to the diagnosis of TAO. INTERVENTIONS: The patient was instructed to stop smoking, but was unable to do so. OUTCOMES: Nine months after the completion of radiotherapy, fecaluria appeared, and a rectourethral fistula was diagnosed by contrast enema. The patient's TAO was poorly controlled, and the patient died from aspiration pneumonia 33 months after completion of the radiotherapy regimen. No tumor recurrence was observed during this process, and there were no risk factors other than TAO that may have formed a rectourethral fistula. LESSONS: This is the first report of rectourethral fistula caused by external beam radiotherapy for prostate cancer in which TAO was suspected to be involved. Although little is known about the relationship between TAO and radiotherapy, it should be noted that radiotherapy itself may increase the risk of normal tissue toxicity in patients with TAO.

A newly developed patient fixation system using a dedicated mouthpiece and dental impression materials for head and neck radiotherapy: a preliminary study.

We evaluated the basic characteristics and efficacy of our newly developed patient fixation system for head and neck radiotherapy that uses a dedicated mouthpiece and dental impression materials. The present investigation demonstrated that with this system, the changes in the absorbed dose to water depending on the material of the mouthpiece were small, with a maximum of 0.32% for a 10-MV photon beam. For the dental impression material, we selected a silicone material with the lowest Hounsfield unit (HU) value that had little effect on the generation of artifacts and the quality of the X-ray beam. Multiphase magnetic resonance imaging (MRI) revealed that the head-up and -down motions in the thermoplastic shell without the mouthpiece were 5.76 ± 1.54 mm, whereas the motion with the mouthpiece decreased significantly to 1.72 ± 0.92 mm (P = 0.006). Similarly, the head-left and -right motion displacement decreased from 6.32 ± 1.86 mm without the mouthpiece to 1.80 ± 0.42 mm with the mouthpiece (P = 0.003). Regarding the tongue depressor function of the mouthpiece, the median distance from the hard palate to the surface of the tongue was 28.42 mm. The present results indicate that the new immobilization device developed herein that uses a mouthpiece and a thermoplastic shell is useful for suppressing patients' head motions and tongue positions.

Bicuspidalization of the Native Tricuspid Aortic Valve: A Porcine in Vivo Model of Bicuspid Aortopathy.

Objective: To examine early histologic changes in the aorta exposed to bicuspid flow. Material and Methods: A porcine bicuspid aortopathy model was developed by suturing aortic cusps. Of nine pigs, eight underwent sham surgery (n=3) or bicuspidalization (n=5); one was used as an intact control. Wall shear stress (WSS) was assessed by computational fluid dynamics (CFD). Animals were exposed to normal or bicuspid flow for 48 h and were then euthanized for histologic examinations. Results: No animal died intraoperatively. One animal subjected to bicuspidalization died of respiratory failure during postoperative imaging studies. Echocardiography showed the aortic valve area decreased from 2.52±1.15 to 1.21±0.48 cm2 after bicuspidalization, CFD revealed increased maximum WSS (10.0±5.2 vs. 54.0±25.7 Pa; P=0.036) and percentage area of increased WSS (>5 Pa) in the ascending aorta (30.3%±24.1% vs. 81.3%±13.4%; P=0.015) after bicuspidalization. Hematoxylin-eosin staining and transmission electron microscopy showed subintimal edema and detached or degenerated endothelial cells following both sham surgery and bicuspidalization, regardless of WSS distribution. Conclusion: A bicuspid aortic valve appears to increase aortic WSS. The endothelial damage observed might have been related to non-pulsatile flow (cardiopulmonary bypass). Chronic experiments are needed to clarify the relationship between hemodynamic stress and development of bicuspid aortopathy.

Minimized perfusion circuit for acute type A aortic dissection surgery.

A minimized perfusion circuit (MPC) may reduce transfusion requirement and inflammatory response. Its use, however, has not been standardized for complicated cardiovascular surgery. We assessed outcomes of surgery for acute type A aortic dissection (ATAAD) performed with a MPC under circulatory arrest. The study involved 706 patients treated surgically for ATAAD (by hemiarch repair [n = 571] or total arch repair [n = 135]). Total arch repair was performed using selective antegrade cerebral perfusion. Our MPC, a semi-closed bypass system, incorporating a completely closed circuit and a level-sensing reservoir in the venous circuit, was used. Clinical variables, transfusion volume, and outcomes were investigated in patients who underwent hemiarch repair or total arch repair. The overall incidences of shock, organ ischemia, and coagulopathy (prothrombin time-international normalized ratio >1.5) were 26%, 35%, and 8%, respectively. Mean extracorporeal circulation (ECC) time was 149 minutes for the hemiarch repair group and 241 minutes for the total arch repair group, respectively. No patient required conversion to conventional ECC, and there were no complications related to the use of the MPC. The need for transfusion (98% vs. 91%, P = .017) and median transfusion volume (1970 vs. 1680 mL, P = .002) was increased in the total arch repair group. Neither in-hospital mortality (total arch; 12% vs. hemiarch; 7%, P = .11) nor 10-year survival (74.4% vs. 68.4%, P = .79) differed significantly. Outcomes of surgery for ATAAD performed with the MPC were acceptable. The possibility of transfusion and transfusion volume remains high during such surgery, despite the use of the MPC.

Development of a new control device for stabilizing blood level in reservoir during extracorporeal circulation.

We developed a simple device that stabilizes the blood level in the reservoir of the extracorporeal circulation open circuit system by measuring the hydrostatic pressure of the reservoir to control the flow rate of the arterial pump. When the flow rate of the venous return decreases, the rotation speed of the arterial pump is automatically slowed down. Consequently, the blood level in the reservoir is stabilized quickly between two arbitrarily set levels and never falls below the pre-set low level. We conducted a basic experiment to verify the operation of the device, using a mock circuit with water. Commercially available pumps and reservoir were used without modification. The results confirmed that the control method effectively regulates the reservoir liquid level and is highly reliable. The device possibly also functions as a safety device.