Nagoya Journal of Medical Science

The adoption of lumbar fusion techniques, particularly lateral lumbar interbody fusion (LLIF), has significantly evolved the management of degenerative lumbar spinal conditions. LLIF, introduced as a minimally invasive surgical procedure, offers the advantage of indirect neural decompression and robust bone fusion using large interbody cages, reducing complications such as cage subsidence and nerve injuries. Systematic reviews have indicated that LLIF was effective for foraminal decompression, although evidence regarding its effectiveness for spinal canal and lateral recess decompression remains limited. Comparisons between indirect decompression techniques like LLIF and direct methods (posterior lumbar interbody fusion and transforaminal lumbar interbody fusion) have revealed that while indirect approaches generally promoted lower surgical times and blood loss, outcomes related to pain, disability, and complications were comparable. Indirect decompression with LLIF should be approached cautiously or avoided in patients with severe stenosis or preoperative neurological impairments due to the increased risk for postoperative complications. Furthermore, meticulous surgical planning and advanced imaging techniques are essential for mitigating risks such as vascular, bowel, and ureteral injuries. Continued advancements in surgical instrumentation and navigation technologies are expected to further refine the utility of LLIF in treating complex spinal pathologies, offering a promising minimally invasive option for achieving effective spinal stabilization and decompression.

Calcium chloride (CaCl₂)-containing carbon dioxide (CO₂) absorbers are characterized by their ability to produce almost no pentafluoroisopropenyl fluoromethyl ether (Compound A), a potentially nephrotoxic byproduct of sevoflurane, in vitro. However, the precise role of CaCl₂ in this process remains unclear. We aimed to clarify the role of CaCl₂ in vitro and determine whether CaCl₂-containing CO₂ absorbents produce Compound A during prolonged surgery under low- and minimal-flow sevoflurane anesthesia using Japanese brand Yabashi Lime-f (YL-f). In vitro, a reaction between 1 L of sevoflurane gas (8%) with 5% CO₂ and an absorbent specimen (20 g) with or without water was performed in an artificial closed-circuit system for 15 or 60 min at 45 °C. In vivo, patients scheduled for colorectal resection received 2.0 vol% sevoflurane at fresh gas flows of 2.0, 1.0, or 0.5 L/min (N = 6) with YL-f. Gas samples from the anesthetic circuit were collected 6 h after induction and at the conclusion of surgeries lasting over 7 h. Compound A concentrations were measured using gas chromatography-flame ionization detection. Compound A production was observed in CaCl₂-free absorbents but not in those containing CaCl₂ in vitro. During 60-min reactions, CaCl₂-free YL-f derivatives produced a median 3.5 ppm of Compound A, with higher concentrations (7.1 ppm) observed upon the addition of 3 mL of water. YL-f did not produce Compound A, regardless of the presence of water. Compound A was not detected in in vivo samples. In conclusion, CaCl₂ suppresses Compound A production from sevoflurane, likely by trapping water within the anesthetic circuit.

Small municipalities have few users with specific health guidance, which makes accurate evaluation difficult. This study verified the effectiveness of specific health guidance using data from specific health checkups and specific health guidance from a municipality in Gifu Prefecture over 7 years. The data were provided by Kokuho Database (KDB; National Health Insurance database) system and included 3,786 individuals who underwent a specific health checkup for the first time between 2008 and 2014, followed by another check the subsequent year. I calculated the differences in weight, body mass index (BMI), and waist circumference from the year of the health check to the weight, BMI, and waist circumference between the initial and the following year's checks based on health guidance usage status. I also evaluated whether there was a difference in the median and metabolic syndrome status in the following year. Weight, BMI, and waist circumference improvements were observed in the group that received health guidance at both incentive and active support groups. In the incentive support group, less than 40% of those who went from the preliminary group became the non-applicable group and more than 40% of those who went from applicable group also became the non-applicable group. In the active support group, less than 80% of those who moved from the preliminary group became the non-applicable group, while less than 30% of those who went from the applicable group also became the non-applicable group.

Bone regeneration is a highly demanded but challenging clinical endeavor in orthopedic surgery, necessitating the development of alternative bone grafting materials. This study aimed to evaluate the bone regenerative potential of self-assembling peptide hydrogel (0.8%), bone morphogenetic protein-2 (50 ng/μL), hydroxyapatite, and β-tricalcium phosphate, both individually and in combination with bone chips, in a rat femoral defect model. Ten-week-old female Wistar rats underwent surgical implantation of a polyetheretherketone cage into a 5-mm bony defect within the left femoral mid-shaft, maintained by an external fixator. Polyetheretherketone cages were filled with bone substitute materials alone in the first experiment and with bone substitute materials combined with bone chips in the second experiment. Radiographic and histological analyses were conducted following sacrifice at 56 weeks. While self-assembling peptide hydrogel alone exhibited moderate bone formation, with a bone-volume-to-total-volume ratio of 0.34 ± 0.09, this value was not significantly higher than that of the control group with an empty polyetheretherketone cage. Conversely, the combination of bone morphogenetic protein-2 with bone chips produced the highest level of bone regeneration, with a bone-volume-to-total-volume ratio of 0.78 ± 0.05, significantly surpassing bone chips alone (p < 0.01) and self-assembling peptide hydrogel with bone chips (p < 0.05). These findings suggest that while self-assembling peptide hydrogel holds potential as a scaffold material, particularly in minimally invasive applications, its efficacy in promoting robust bone regeneration may benefit from the inclusion of osteoinductive factors, such as bone morphogenetic protein-2.

Glycosylation, a key post-translational modification, regulates protein function in many contexts. Epidermal growth factor-like repeats undergo domain-specific O-glycosylation such as O-glucosylation, O-fucosylation, and O-GlcNAc'ylation. O-Glucose glycans are attached to specific serine residues by the action of protein O-glucosyltransferase 1 (POGLUT1) and can be elongated with two xylose residues by glucoside α1-3xylosyltransferase 1 (GXYLT1) or glucoside α1-3xylosyltransferase 2 (GXYLT2) and xyloside α1-3xylosyltransferase 1 (XXYLT1) in mammals. The xylosyl elongation of O-glucose as a negative regulator of Notch in Drosophila has recently been reported, but its role in mammalian Notch signaling remains elusive. Here, we investigated the impact of terminal xylosylation by XXYLT1 on NOTCH1 signaling in Jurkat cells, a T-cell acute lymphoblastic leukemia cell line with cell-autonomous NOTCH1 activation due to the juxtamembrane expansion mutation. Mass spectrometry analysis of NOTCH1 fragments overexpressed in Jurkat cells demonstrated that the O-glucose site on NOTCH1 EGF10 was modified with various elongating patterns of O-glucose. Genetic deletion of XXYLT1 in Jurkat cells led to enhanced activation of NOTCH1, suggesting that XXYLT1 inhibited NOTCH1 activation in Jurkat cells, whereas the cell surface expression of NOTCH1 was not altered. Unexpectedly, the proliferation of Jurkat cells was impaired in XXYLT1 knockout cells, with accompanying MYC downregulation, a Notch target gene. Our results revealed for the first time that mammalian Notch activation is fine-tuned by xylosylation in Jurkat cells, thus highlighting the potential of Notch agonism by the inhibition of xylosylation. Additionally, our findings regarding cell proliferation underscore the notion that there are possibly substrates other than NOTCH1 that XXYLT1 modifies, thereby regulating their functions in Jurkat cells.

Sarcopenia, a condition characterized by the loss of muscle mass and function, poses a major health challenge among older adults. Identifying nutritional factors and dietary patterns associated with sarcopenia is critical for developing targeted interventions. This study analyzed data from 584 community-dwelling older adults (245 male, 339 female) enrolled in the Yakumo Study to investigate the relationship between dietary factors and sarcopenia. Nutritional intake was assessed using a validated Food Frequency Questionnaire (FFQ), while dietary diversity was evaluated using dietary variety score (DVS). Sarcopenia was diagnosed according to the Asian Working Group for Sarcopenia (AWGS) criteria, based on skeletal muscle mass, hand grip strength, and walking speed. The prevalence of sarcopenia in the study population was 7.4%. Nutritional intake of individual nutrients, such as protein and vitamin D, did not significantly differ between sarcopenic and non-sarcopenic participants. However, the intake rates for total calories, dietary fiber, vitamin B1, vitamin B2, and vitamin C were significantly higher in the sarcopenia group. No significant differences were found in DVS, and no correlations were found between DVS scores and skeletal muscle mass index, grip strength, or walking speed. These results may indicate that factors beyond nutrient intake—such as nutrient absorption, utilization, and metabolic efficiency—play a pivotal role in sarcopenia development.

Shear wave elastography provides quantitative data on tissue stiffness, but was not available for endoscopic ultrasound until recently. The present study investigated the utility of a newly developed endoscopic ultrasound-guided shear wave measurement for diagnosing upper gastrointestinal subepithelial lesions. Shear wave velocity (Vs) was measured as an indicator of tissue stiffness, and the total amount of effective shear waves (VsN) was used as a reliability index for Vs values obtained by endoscopic ultrasound-guided shear wave measurements. Among the Vs values obtained, the five with the highest VsN were selected, and their median was defined as the median Vs (Vs-med). The median VsN of the five Vs values was defined as the median VsN (VsN-med). Endoscopic ultrasound-guided shear wave measurements were performed on 23 patients, with no complications occurring in any procedure. Histopathological diagnoses included 12 gastrointestinal stromal tumors, seven leiomyomas, and four schwannomas. Vs-med values for gastrointestinal stromal tumors, leiomyomas, and schwannomas were 2.46, 1.73, and 2.85 m/s, respectively, indicating that gastrointestinal stromal tumors and schwannomas were significantly stiffer than leiomyomas. VsN-med values for gastrointestinal stromal tumors, leiomyomas, and schwannomas were 40.5, 39, and 35.5%, respectively, with no significant differences. Endoscopic ultrasound-guided shear wave measurements are feasible for upper gastrointestinal subepithelial lesions and allow for the objective, non-invasive quantification of lesion stiffness. These results suggest the potential of endoscopic ultrasound-guided shear wave measurements as a valuable tool for the differential diagnosis of upper gastrointestinal subepithelial lesions.

This study investigates the relationship between gratitude and presenteeism (working while unwell) among workers. Productivity loss due to health issues among workers is a critical problem. The largest portion of health-related costs comes from presenteeism, with mental disorders being the main contributors. Gratitude, as one of the positive psychological factors, might have a protective effect against presenteeism. This is because gratitude can reduce stress, increase support from others, improve the workplace atmosphere, and enhance self-efficacy. Therefore, we hypothesized that higher trait gratitude (individual differences in the tendency to feel gratitude) and higher frequency of gratitude expression would be associated with lower levels of presenteeism. In 2022, a cross-sectional study was conducted with workers in Tsukuba City. The outcome variable was the Single-item Presenteeism Question, which is an indicator of presenteeism. The explanatory variables included the Gratitude at Work Scale, a measure of trait gratitude in workplace, along with frequency of expressing gratitude. Multiple regression analysis was performed. The results showed that higher trait gratitude was associated with lower levels of presenteeism (standardized coefficient, –0.203; p < 0.001). Higher frequency of gratitude expression was associated with lower levels of presenteeism (standardized coefficient, -0.048; p = 0.016). The study confirmed that trait gratitude and frequency of gratitude expression were associated with presenteeism. However, it remains unclear whether gratitude directly reduces presenteeism, and further longitudinal studies are needed to explore this possibility.

Pemetrexed, a structural antifolate agent that is eliminated via renal excretion, is commonly used to treat non-squamous non-small-cell lung cancer (NS-NSCLC). Although poor renal function is associated with a high incidence of toxicities, the association of high renal function with chemotherapy efficacy and toxicity remains unknown. We aimed to investigate the effect of renal function on the efficacy and toxicity of carboplatin-pemetrexed chemotherapy in patients with NS-NSCLC. We performed a post-hoc analysis of a prospective observational study of carboplatin-pemetrexed treatment in NS-NSCLC patients. Baseline renal function was calculated using the Japanese estimated glomerular filtration rate (eGFR) formula, and the patients were then divided into two groups based on the eGFR: high-eGFR (eGFR ≥ 80 mL/min/1.73 m², N = 162) and low-eGFR (eGFR < 80 mL/min/1.73 m², N = 176) groups. Although the response rates in the high- and low-eGFR groups were similar (22.2% vs 23.9%, P = 0.7205), the disease control rate was significantly lower in the high-eGFR group than in the low-eGFR group (75.9% vs 84.7%, P = 0.043). Progression-free survival (PFS) and overall survival (OS) in the high-eGFR group were significantly shorter than those in the low-eGFR group (adjusted hazard ratio for PFS and OS, 1.32 [95% CI, 1.04–1.69; P = 0.0245] and 1.49 [95% CI, 1.15–1.93, P = 0.0023], respectively). The incidence of hematological and non-hematological toxicities was lower in the high-eGFR group. In conclusion, a high-eGFR is associated with poor efficacy and mild toxicity of carboplatin-pemetrexed in patients with NSCLC.

Maternal depression affects 17.7% of postpartum women and can emerge years after childbirth, impacting both mothers and their children. Social support plays an important role in preventing maternal depression. Family and community were traditional sources of social support, but the rise of digital media may impact social support and therefore maternal well-being. Mothers are accustomed to technology and often use digital devices for childcare and leisure activities. This study examined the association between screen time and the onset of depression two years postpartum. A cohort study was initiated in November 2020 (baseline) with follow-up in May-June 2022, employing an anonymous online questionnaire. Study participants were first-time mothers (n = 204) of children aged 5–8 months. Measures considered basic attributes, family environment, maternal depression (Edinburgh Postnatal Depression Scale [EPDS]), screen time, and sleep status. No baseline maternal depression (EPDS score < 9) was a requirement for participation. Maternal depression onset during a 1.5-year follow-up was the dependent variable. Screen time, sleep duration, and support services were independent variables. Their relationships were analyzed using Fisher's exact test, the Mantel-Haenszel test, and logistic regression. Twenty-six participants (12.7%) developed depression (EPDS ≥ 9) within two years of childbirth. Logistic regression revealed a significant association between smartphone use time and maternal depression (odds ratio [OR] = 1.89; 95% confidence interval [CI], 1.09–3.26). No association was found between social media or game use and maternal depression. Excessive smartphone use was related to depression two years after childbirth, indicating the need for health guidance on screen time for mothers.

Microglia are brain specific macrophages and the only immune cells in the brain. Microglia sense the systemic immune status and contribute to neurological and psychiatric disorders. We previously showed that systemic immune activation induces microglial migration on vessels that regulate the blood brain barrier permeability. In this study, using Toll like receptor 7 induced systemic lupus erythematosus model mice, we found microglia migration on vessels and significant T cell infiltration in the brain. Additionally, microglia interacting with T cell expressed MHC class II molecules in some cases, suggesting the antigen presentation of microglia in systemic lupus erythematosus model mice. This research provides insights on the autoimmune antibody expression in the brain.

Cerebrospinal fluid (CSF) leakage is a common and serious complication of spinal surgery, particularly after intradural tumor resection. CSF leakage can lead to debilitating headaches, neurological deficits, and other symptoms, with an incidence rate of 0.3%–16%. This study aimed to investigate the incidence, risk factors, and outcomes of CSF-related complications in patients who underwent spinal intradural tumor surgery. This was a retrospective cohort study including 102 patients who underwent resection of intradural tumors, including ependymomas, astrocytomas, and meningiomas. Data were collected, including patient demographics, surgical details, and postoperative outcomes. The extent of CSF accumulation was evaluated using magnetic resonance imaging (MRI) findings. Statistical analyses were performed to identify risk factors for symptomatic CSF leakage. Postoperative CSF accumulation was observed in 94.1% of patients. Among them, 28.1% experienced symptomatic complications, such as severe headache (20.8%), unexplained fever (6.3%), and CSF leakage (3.1%). Patients with larger CSF accumulation, particularly subcutaneous accumulation, had a significantly higher incidence of symptomatic complications, with the highest rate observed in subfascial accumulation cases (P = 0.0002). Symptomatic patients did not show significant differences in age, sex, surgical level, drainage duration, or blood loss compared to asymptomatic patients. Additionally, the use of artificial dura mater did not significantly affect symptomatic outcomes. Predicting the occurrence of symptoms based on preoperative and surgical factors remains challenging. However, patients with subfascial CSF accumulation were more likely to develop symptoms, highlighting the necessity of confirming CSF accumulation using MRI for appropriate postoperative management.

Chronic kidney disease (CKD) and its treatment with hemodialysis (HD) pose unique challenges for spinal surgery due to complications such as destructive spondyloarthropathy (DSA). This study retrospectively compared the surgical outcomes of posterior lumbar interbody fusion (PLIF) between 48 HD patients and 57 non-HD controls. Patients with tumors, infections, prior spinal surgery, or severe osteoporosis were excluded. HD patients had a mean dialysis duration of 16.2 years, while controls were treated for degenerative lumbar conditions. HD patients exhibited significantly higher intraoperative blood loss (415.8 ± 231.7 mL vs 293.4 ± 57.3 mL, P < 0.001) and lower 2-year bony fusion rates (72.9% vs 94.7%, P = 0.008). Pseudoarthrosis and adjacent segment disease (ASD) were more common in the HD group, necessitating reoperation in five cases versus one in controls. Neurological recovery at 2 years was worse in the HD group, with a mean Japanese Orthopaedic Association score of 19.6 ± 4.3 compared to 26.5 ± 2.2 in controls (P < 0.01). Despite facilitating initial neurological recovery, PLIF outcomes in HD patients were compromised by greater complication rates, including pseudoarthrosis and ASD. Thus, PLIF facilitates early neurological improvement in HD patients, but long-term functional outcomes are compromised due to higher rates of pseudoarthrosis and ASD, necessitating careful long-term management. Strategies minimizing mechanical stress and maintaining spinal alignment could further support long-term patient recovery.

The segmental innervation patterns of lower extremity muscles remain poorly defined, despite their critical importance in both clinical diagnosis and surgical planning for lumbar spinal conditions. Variability in these patterns, particularly under chronic nerve root compression, complicates the development of accurate diagnostic and therapeutic strategies. This study aimed to elucidate the segmental innervation patterns of lower extremity muscles through intraoperative nerve root stimulation during lumbar spinal surgery combined with motor evoked potential (MEP) during lumbar spinal surgery. A total of 30 patients diagnosed with unilateral nerve root impairment due to degenerative lumbar canal stenosis were enrolled in this study. All patients provided informed consent, demonstrated lower extremity muscle strength graded 4 or higher on the manual muscle test, and were scheduled for surgeries that enabled direct visualization of bilateral nerve roots. During the surgical procedures, 128 lumbosacral nerve roots (L2–S1) were stimulated using a monopolar stimulator, and MEPs were recorded from key lower extremity muscles, including the vastus lateralis, tibialis anterior, and medial gastrocnemius. The vastus lateralis muscle was consistently innervated by the L2 root in 100% of cases, confirming a stable and reproducible pattern. In contrast, stimulation of the L5 root revealed notable anomalies in 8% of cases, where compensatory mechanisms or anatomical anomalies appeared to alter the expected innervation patterns. Furthermore, differences in muscle innervation between the left and right sides were observed in 39% of tested nerve roots, with variability being particularly pronounced in lower lumbar levels, such as L4, L5, and S1.

While preoperative antibiotic therapy is generally recommended in non-emergency surgery cases of infective endocarditis, delaying surgery may lead to a deterioration in patient condition. This study examined deterioration of condition during preoperative antibiotic therapy and associated clinical characteristics to clarify the optimal timing for non-emergent infective endocarditis surgery. We retrospectively analyzed 65 patients (mean age 57.1 ± 16.9 years) with active left-sided infective endocarditis (57 with native valves, 8 with prosthetic valves) initially considered suitable for combined antibiotic therapy and non-emergent surgical treatment. Causative organisms were Streptococcus spp. (n=31), Staphylococcus spp. (n=15, including 5 resistant strains), and Gram-negative bacteria (n=4). Twelve patients (18%) required unexpected urgent operations shortly after starting antibiotics (median 5.5 days, interquartile range 3–8 days). Another 12 patients (18%) experienced deterioration of condition 20–30 days after starting antibiotics, including worsening heart failure (n=5), new embolic events (n=3), new perivalvular extension of infection (n=3), and worsening infection parameters (n=1). A leukocyte count >7900/μL one week after starting antibiotics predicted late deterioration (sensitivity 91%, specificity 76%, area under the receiver operating characteristic curve 0.866). Among patients with active infective endocarditis who initially received maximal antibiotic therapy and were considered for non-emergent surgery, 18% required urgent operation and another 18% experienced late deterioration. A high leukocyte count despite one week of antibiotic therapy was associated with late deterioration. For these patients, earlier surgical intervention might be beneficial to avoid a deterioration in conditions.

We performed total aortic arch replacement (TAR) with a frozen elephant trunk (FET) for chronic dissecting aortic aneurysm (DAA) involving the aortic arch as the initial surgery and carefully observed these aortic findings with periodic computed tomography (CT) follow-up. Additional surgical interventions were considered when aortic events were observed. Midterm outcomes were evaluated to clarify the feasibility of this strategy. Thirty-seven patients underwent TAR with FET between 2014 and 2020. The median follow-up period was 48.6 months. There was 1 case of operative mortality (2.7%) and 11 late deaths, including five aortic-related deaths. Aortic events occurred in 26 patients (72.2%), including 14 cases of stent-induced new entry (SINE), eight cases of aneurysmal enlargement, two cases of graft infection, and one each of additional aortic dissection and aortic root enlargement. Thirty-one procedures were performed, including 14 open surgeries, 16 thoracic endovascular aortic repairs (TEVAR), and 1 endovascular aortic repair (EVAR) with coil embolization. The freedom rate from aortic events was 36.9% at three years and 22.8% at five years. The distal aortic arch showed significant shrinking (slope, –1.96; P<0.001), but the lower descending aorta showed significant enlargement (slope, 0.87; P<0.001). The diameter of the middle descending aorta was a predictor of SINE (>40.5 mm) and aneurysm enlargement (>40.2 mm). The present study showed acceptable early outcomes but frequent aortic events during follow-up. Cautious periodic CT is mandatory to perform additional reinterventions at the proper time, and scheduled surgical intervention, including TEVAR, is essential for cases with enlarged middle descending aortas.

Atypical hemolytic uremic syndrome (aHUS) is a rare and life-threatening disease often complicated by end-stage renal disease. Anti-C5 antibody agents have been developed for the treatment of aHUS: these are highly effective but limited in use owing to the difficulty of diagnosing aHUS in the acute clinical phase. The pathophysiology of aHUS is a thrombotic microangiopathy (TMA) caused by complement dysregulation triggered by environmental factors in susceptible individuals with genetic factors. Although several germline variants associated with aHUS have been identified, approximately half of patients with aHUS lack known pathogenic variants. It is essential to recognize the characteristic clinical features of aHUS. These include the triad of hemolytic anemia, thrombocytopenia, and renal impairment, without the presence of Shiga toxin-producing Escherichia coli infection, thrombotic thrombocytopenic purpura associated with ADAMTS13 deficiency, or TMA from secondary cause. In this case, plasma exchange could not be continued owing to allergy. Early diagnosis allowed for prompt administration of eculizumab at the time of relapse, with favorable outcomes. Based on the finding of no genetic abnormalities, eculizumab was discontinued after 12 months, with no recurrence for 3 years. On day 27 of hospitalization, renal biopsy revealed endothelial damage. Since a definitive diagnosis cannot be made with genetic testing in the acute stage and approximately half of patients have no genetic abnormalities, it is suggested to diagnose the condition as per the clinical definition and commence treatment with plasma exchange. If thrombotic thrombocytopenic purpura is excluded, switching to eculizumab is another treatment option according to clinical conditions.

We report the case of an 80-year-old woman with a medial thigh nodule who was diagnosed with primary cutaneous diffuse large B-cell lymphoma, leg type. Further examination identified it as double-expressor lymphoma with elevated expression of both MYC and BCL2. This elevated expression has been linked to MYC translocation and is likely associated with trisomy 18. Our findings suggest that trisomy 18 plays a significant role in the development of double-expressor lymphoma. While cases of double-expressor lymphoma caused by extra copies of BCL2 have been reported, we could not find any case of double-expressor lymphoma caused by trisomy 18. Therefore, this is an unique case of double-expressor lymphoma linked to MYC rearrangement and trisomy 18. Double-expressor lymphoma typically has a poor prognosis and is often resistant to standard treatments. The current findings may help refine diagnostic strategies for this condition.

Hemolytic anemia is a rare complication after aortic surgery. We herein report an early postoperative case of hemolytic anemia caused by an internal felt strip. A 57-year-old man underwent emergency partial aortic arch replacement for acute type A aortic dissection. The proximal stump was reinforced using internal and external polytetrafluoroethylene felt strips. The patient subsequently developed profound mechanical hemolytic anemia two weeks after the operation. Computed tomography did not reveal any narrowing of the anastomosis or kinking of the graft. However, transesophageal echocardiography confirmed that the internal felt strip had become inverted by the blood flow. Reoperation was performed to redo the proximal anastomosis, while also removing the internal felt strip. Hemolysis diminished soon after the reoperation. We encountered a case of acute aortic dissection that required reoperation because of hemolytic anemia caused by internal felt strip inversion. Further measures are required to prevent hemolysis with felt strips.