Two sizes of acetaminophen injection, 500 and 1,000 mg, have been approved for use in the USA and Europe, while only 1,000 mg has been approved in Japan. In Japan, overdosage of intravenous acetaminophen has been reported in pediatric patients. It is necessary align with international practices and introduce a 500 mg dosage, as in the USA and Europe. Therefore, we conducted a 6-month survey at Kyoto Chubu Medical Center from October 2020, focusing on single dose intravenous acetaminophen. Out of 400 cases, 333 (83.3%) received a single dose of 1,000 mg, 49 cases (12.3%) received 500 mg. Among children (< 15 years), all 17 cases (100%) received a single dose of 500 mg or less; in adults (≥ 15 years), out of 383 cases, 45 cases (11.7%) received 500 mg or less. The most commonly used single dose of intravenous acetaminophen was 1,000 mg, followed by 500 mg. These findings suggest that 1,000 mg is less necessary in children if 500 mg is available, and that, in adults, 1,000 mg may not always be required. In Japan, to avoid overdose in children and optimize dosage in adults, early introduction of 500 mg intravenous acetaminophen is crucial.

Methods: This study included 46 patients who underwent spinal reconstruction surgery for thoracolumbar osteoporotic vertebral fractures and kyphosis and were followed up for 1 year postoperatively. DJK was defined as an advanced kyphosis angle >10° between the LIV and one lower vertebra. The patients were divided into groups with and without DJK. The risk factors of the two groups, such as patient background, surgery-related factors, radiographic parameters, and clinical outcomes, were analyzed. Results: The DJK and non-DJK groups included 14 and 32 patients, respectively, without significant differences in patient background. Those with instability in the distal adjacent LIV disc had a significantly higher risk of DJK occurrence (28.6% vs. 3.2%, p=0.027). DJK occurrence significantly increased in those with the sagittal stable vertebra not included in the fixation range (57.1% vs. 18.8%, p=0.020). Other preoperative radiographic parameters were not significantly different. Instability in the distal adjacent LIV disc (adjusted odds ratio, 14.50; p=0.029) and the exclusion of the sagittal stable vertebra from the fixation range (adjusted odds ratio, 5.29; p=0.020) were significant risk factors for DJK occurrence. Conclusions Regarding spinal reconstruction surgery in patients with osteoporotic vertebral fractures, instability in the distal adjacent LIV disc and the exclusion of the sagittal stable vertebra from the fixation range were risk factors for DJK occurrence in the short term.

Left ventricle to right atrial communication is a rare cardiac pathology, and it is either congenital or acquired. Recently, case reports of acquired left ventricle to right atrial communication have been increasing because of the increased numbers of cardiovascular procedures and improved cardiac diagnostic techniques. We report a case of acquired left ventricle to right atrial communication in a patient with native aortic valve infective endocarditis. A 52-year-old man with worsening dyspnea on exertion and lower leg edema was admitted to a hospital. Blood examination revealed elevated inflammatory marker levels, and transthoracic echocardiography (TTE) showed an aortic valve vegetation. The patient was subsequently transferred to our hospital for infective endocarditis with congestive heart failure. Medical treatment with antibiotics and diuretics was initiated. Cardiac computed tomography (CT) demonstrated left ventricle to right atrial communication. An urgent operation was performed wherein the defect was closed with autologous pericardial patches from both the right atrium and left ventricle. Aortic valve replacement was performed with a mechanical valve. The postoperative course was uneventful, and TTE showed no residual shunt. In our case, cardiac CT was useful for accurately diagnosing left ventricle to right atrial communication.

Massive rotator cuff tears (RCTs) are complicated by muscle atrophy, fibrosis, and intramuscular fatty degeneration, which are associated with postoperative tendon-to-bone healing failure and poor clinical outcomes. We evaluated muscle and enthesis changes in large tears with or without suprascapular nerve (SN) injury in a rat model. Methods: Sixty-two adult Sprague-Dawley rats were divided into SN injury (+) and SN injury (–) groups (n=31 each), comprising tendon (supraspinatus [SSP]/infraspinatus [ISP]) and nerve resection and tendon resection only cases, respectively. Muscle weight measurement, histological evaluation, and biomechanical testing were performed 4, 8, and 12 weeks postoperatively. Ultrastructural analysis with block face imaging was performed 8 weeks postoperatively. Results: SSP/ISP muscles in the SN injury (+) group appeared atrophic, with increased fatty tissue and decreased muscle weight, compared to those in the control and SN injury (–) groups. Immunoreactivity was only positive in the SN injury (+) group. Myofibril arrangement irregularity and mitochondrial swelling severity, along with number of fatty cells, were higher in the SN injury (+) group than in the SN injury (–) group. The bone-tendon junction enthesis was firm in the SN injury (–) group; this was atrophic and thinner in the SN injury (+) group, with decreased cell density and immature fibrocartilage. Mechanically, the tendon–bone insertion was significantly weaker in the SN injury (+) group than in the control and SN injury (+) groups. Conclusions: In clinical settings, SN injury may cause severe fatty changes and inhibition of postoperative tendon healing in large RCTs. Level of evidence: Basic research, controlled laboratory study

We report a case of arbitrary delayed surgical repair for left ventricular free wall rupture (LVFWR) after acute myocardial infarction with suspected posterior papillary muscle necrosis. The case was a 67-year-old woman who had chest and back pain in the morning, and relapsed in the evening, and was urgently transported. She had an acute lateral wall myocardial infarction on an electrocardiogram and pericardial effusion on transthoracic echocardiography (TTE). She was found to have an obstruction at the origin of the left circumflex branch on coronary angiography. TTE showed low-intensity findings on the head of the posterior papillary muscle, suggesting necrosis of the papillary muscle. For LVFWR, conservative treatment was prioritized and IABP (intra-aortic balloon pumping) management was performed for the purpose of reducing after load because there was concern about papillary muscle rupture (PMR) due to cardiac manipulation and because it was an oozing type and did not disrupt respiratory of circulatory dynamics. On the 7th day after the onset, TTE showed improvement in echo-luminance of the posterior papillary muscle head and gradual increase in pericardial fluid, and a non-suture procedure was performed. She withdrew from the IABP on the third day after surgery and was discharged home on the 12th day.