Isolation of ependymal cilia from mouse brain.

BACKGROUND: Ependymal cilia play a major role in the circulation of cerebrospinal fluid. Although isolation of cilia is an essential technique for investigating ciliary structure, to the best of our knowledge, no report on the isolation and structural analysis of ependymal cilia from mouse brain is available. NEW METHOD: We developed a novel method for isolating ependymal cilia from mouse brain ventricles. We isolated ependymal cilia by partially opening the lateral ventricles and gently applying shear stress, followed by pipetting and ultracentrifugation. RESULTS: Using this new method, we were able to observe cilia separately. The results demonstrated that our method successfully isolated intact ependymal cilia with preserved morphology and ultrastructure. In this procedure, the ventricular ependymal cell layer was partially detached. COMPARISON WITH EXISTING METHODS: Compared to existing methods for isolating cilia from other tissues, our method is meticulously tailored for extracting ependymal cilia from the mouse brain. Designed with a keen understanding of the fragility of the ventricular ependyma, our method prioritizes minimizing tissue damage during the isolation procedure. CONCLUSIONS: We isolated ependymal cilia from mouse brain by applying shear stress selectively to the ventricles. Our method can be used to conduct more detailed studies on the structure of ependymal cilia.

Safety and efficacy of the endoscopic transsphenoidal transclival approach performed using direct cortical stimulation for pontine cavernous malformations.

OBJECTIVE: Surgical treatment of brainstem cavernous malformations (CMs) is challenging. Surgery using the endoscopic transsphenoidal transclival approach (eTSTCA) is reported as a useful alternative for ventral brainstem CMs. However, CMs located in the ventral midline of the brainstem are rare, and only a small number of case reports on these CMs treated with the eTSTCA exist. The efficacy and safety of the eTSTCA have not yet been fully examined. METHODS: A retrospective analysis was performed for 5 consecutive patients who underwent surgery via the eTSTCA for treating ventral pontine CMs. RESULTS: The average maximum CM diameter was 26.0 mm (18-38 mm). All patients underwent MR-diffusion tensor imaging, which confirmed that the corticospinal tract (CST) deviated posteriorly or laterally to the CM. Direct brainstem cortical stimulation was performed to localize the CST before making the cortical incision. After the excision of the CM, the cavity was filled with artificial CSF to make an aqueous surgical field (wet-field technique) for observing the tumor cavity and confirming complete hemostasis and resection. Total removal was achieved in all patients. The preoperative modified Rankin Scale score was 3 in 3 patients and 4 in 2 patients, whereas it was 1 in 2 patients and 0 in 3 patients 3 months after surgery. Postoperative CSF leakage was observed in 1 patient, and transient abducens nerve palsy was observed in 1 patient. No other intra- or postoperative complications were observed. CONCLUSIONS: MR-diffusion tensor imaging and direct brainstem cortical stimulation were useful to ascertain the proximity of the CST to the CM. The endoscope provides a clear view even underwater, and it was safe and effective to observe the entire CM cavity and confirm complete hemostasis without additional retraction of the brainstem parenchyma, including the CST. The eTSTCA provides a direct access point to the lesion and may be a safer alternative treatment for patients whose CST deviates laterally or posteriorly to the CM.

Effect of embolization before stereotactic radiosurgery for brain arteriovenous malformations: a case-control study with propensity score matching.

OBJECTIVE: The aim of this study was to evaluate whether endovascular embolization prior to stereotactic radiosurgery (SRS) has a negative impact on nidus obliteration for patients with arteriovenous malformations (AVMs). METHODS: A total of 704 eligible patients with AVM who did not undergo prior surgery or radiotherapy were evaluated. Of these patients, 593 were treated with SRS only, and 111 were treated with embolization followed by SRS (E+SRS). Most patients in the E+SRS group (88%) underwent embolization with n-butyl-2-cyanoacrylate. In the comparison of radiosurgical outcomes between patients treated with SRS only and E+SRS, these groups were matched in a 1:1 ratio using propensity score matching to eliminate differences in basic characteristics. The primary outcome was to compare the nidus obliteration rates between the SRS-only and E+SRS groups. The secondary outcomes were the comparison of cumulative hemorrhage rates and the incidence of cyst formation or chronic encapsulated hematoma after SRS between these groups. RESULTS: In the unmatched cohorts, the actuarial 3-, 5-, and 8-year nidus obliteration rates after a single SRS session were 49.6%, 69.4%, and 74.1% in the SRS-only group, respectively, and 30.7%, 50.9%, and 68.6% in the E+SRS group, respectively (p = 0.001). In the matched cohort of 98 patients in each group, the rates were 47.1%, 62.0%, and 69.6% in the SRS-only group and 32.5%, 55.3%, and 75.0% in the E+SRS group, respectively (p = 0.24). There was no significant difference in either cumulative hemorrhage or the incidence of cyst formation or chronic encapsulated hematoma between the groups. CONCLUSIONS: Pre-SRS embolization did not affect nidus obliteration rates, cumulative hemorrhage rates, or the incidence of cyst formation or chronic encapsulated hematoma as late adverse radiation effects in patients with AVM treated with SRS.

The importance of preserving the superior hypophyseal artery infundibular branch in craniopharyngioma surgery.

PURPOSE: Postoperative pituitary dysfunction, a critical problem in the treatment of craniopharyngiomas, can occur even when the pituitary stalk is preserved. We hypothesized that compromise of the primary superior hypophyseal artery (pSHA) might be related to this occurrence. METHODS: We performed a retrospective review of 131 patients with craniopharyngioma who underwent surgery from April 2009 to September 2021. The inclusion criteria were initial surgery, endoscopic transsphenoidal surgery, preoperative normal pituitary function or pituitary dysfunction in one axis, and morphological preservation of the pituitary stalk. The branches of the pSHA consist mainly of the chiasmatic branches (Cb), infundibular branches (Ib), and descending branches (Db). We analyzed the association between postoperative pituitary function and preservation of these branches. RESULTS: Twenty patients met the criteria. Preoperative anterior pituitary function was normal in 18 patients, and there was isolated growth hormone deficiency in two patients. No patient had preoperative diabetes insipidus (DI). Anterior pituitary function was unchanged postoperatively in eight patients. Of these eight patients, bilateral preservation of pSHA Ib was confirmed in seven patients. Bilateral preservation of pSHA Ib was the only factor associated with preserved anterior pituitary function (p < 0.01). Fifteen patients were free of permanent DI, and the preservation of any given pSHA branch produced no significant difference in the postoperative occurrence of permanent DI. CONCLUSIONS: Our study shows that bilateral preservation of pSHA Ib provides favorable postoperative anterior pituitary function in craniopharyngioma surgery; however, such preservation may have little effect on the postoperative occurrence of DI.

Endoscopic Trans-Mini-Cylinder Biopsy for Intraparenchymal Brain Lesions.

OBJECTIVE: The biopsy procedure is intended to obtain an adequate specimen volume from the targeted area while ensuring minimal damage to the normal brain. We performed navigation-guided endoscopic biopsy using a small-diameter cylinder to reduce the invasiveness of the biopsy procedure and ensure a sufficient amount of tissue is collected. We examined whether it is possible to reduce brain tissue injury by using a small-diameter cylinder and improve safety and effectiveness by using an endoscope to directly observe the lesion and achieve hemostasis. METHODS: Patients who underwent endoscopic biopsy surgery using a 6-mm-diameter cylinder for intraparenchymal lesions were enrolled in this study. Postoperative hematoma formation and the extent of trajectory scarring were assessed. RESULTS: Fifty-two procedures performed on 51 patients were analyzed in this study. Postoperative neurological deterioration was not observed in any patient. A pathological diagnosis was made for all patients. Postoperative computed tomography revealed no hematoma after 49 procedures and a small hematoma after 3 procedures, and no patients required additional treatment. A postoperative trajectory scar less than 5 mm in diameter was observed after 30 procedures, a scar of 5-10 mm was observed after 19 procedures, a scar larger than 10 mm was observed after 3 procedures at 1 week after surgery, and 40, 6 and 0 scars were observed at 3 months after surgery. CONCLUSIONS: Endoscopic biopsy using a small-diameter cylinder is a possible alternative biopsy technique for intraparenchymal lesions. This surgical technique is useful, especially in patients at risk of hemorrhagic complications.

Determining Infected Aortic Aneurysm Treatment Using Focused Detection of Helicobacter cinaedi.

We detected Helicobacter cinaedi in 4 of 10 patients with infected aortic aneurysms diagnosed using blood or tissue culture in Aichi, Japan, during September 2017-January 2021. Infected aortic aneurysms caused by H. cinaedi had a higher detection rate and better results after treatment than previously reported, without recurrent infection.

Direct intracranial invasion of eccrine spiradenocarcinoma of the scalp: a case report and literature review.

BACKGROUND: Eccrine spiradenocarcinoma (SC), also known as malignant eccrine spiradenoma, is a rare malignant cutaneous adnexal neoplasm arising from long-standing benign eccrine spiradenoma. Malignant skin tumors rarely show direct intracranial invasion. However, once the intracranial structure is infiltrated, curative excision with sufficient margins can become extremely difficult, particularly when the venous sinuses are involved. No effective adjuvant therapies have yet been established. Here, we report an extremely rare case of scalp eccrine SC with direct intracranial invasion, which does not appear to have been reported previously. CASE PRESENTATION: An 81-year-old woman presented with a large swelling on the parietal scalp 12 years after resection of spiradenoma from the same site. The tumor showed intracranial invasion with involvement of the superior sagittal sinus and repeated recurrences after four surgeries with preservation of the sinus. The histopathological diagnosis was eccrine SC. Adjuvant high-precision external beam radiotherapy (EBRT) proved effective after the third surgery, achieving remission of the residual tumor. The patient died 7 years after the first surgery for SC. CONCLUSIONS: Scalp SC with direct intracranial invasion is extremely rare. Radical resection with tumor-free margins is the mainstay of treatment, but the involvement of venous sinuses makes this unfeasible. High-precision EBRT in combination with maximal resection preserving the venous sinuses could be a treatment option for local tumor control.

Efficacy and safety of the endoscopic "wet-field" technique for removal of supratentorial cavernous malformations.

OBJECTIVE: Cerebral cavernous malformations (CMs) presenting with focal neurological symptoms or mass effects require surgical removal. In recent years, cylindrical retractors have been widely utilized for the removal of deep-seated lesions during both microscopic and endoscopic surgery. In the present study, we evaluated the efficacy and safety of endoscopic transcylinder removal of CMs using a novel wet-field technique. METHODS: We included 13 patients with supratentorial CMs who had undergone endoscopic transcylinder surgery between April 2013 and March 2022. One patient experienced recurrence of the CM and underwent a second endoscopic transcylinder surgery. Therefore, we retrospectively evaluated 14 procedures. The surgical field was continuously irrigated with artificial cerebrospinal fluid to maintain expansion and visualization of the tumor bed. We termed this method as the "wet-field technique." Patient characteristics, symptoms, and pre- and postoperative magnetic resonance imaging results were obtained from medical records. RESULTS: The average maximum CM diameter was 35.3 mm (range: 10-65 mm). Cylinder diameters were 6 mm in eight procedures, 10 mm in four procedures, and 17 mm in one procedure. Wet-field technique was applied in all cases. The endoscope provided a bright field of view even under water. Continuous water irrigation made it easier to observe the entire tumor bed which naturally expanded by water pressure. Gross total resection was achieved in 13 procedures, while subtotal resection was achieved in one procedure. No surgical complications were observed. CONCLUSIONS: The endoscopic transcylinder removal using wet-field technique is safe and effective for the removal of symptomatic intracranial supratentorial CMs.

Modified Shoelace Dural Closure with Collagen Matrix in Extended Transsphenoidal Surgery.

Extended endonasal transsphenoidal surgery (eTSS) offers a wide surgical field for various parasellar lesions; however, intraoperative high-flow cerebrospinal fluid (CSF) leakage is inevitable. Therefore, secure sellar reconstruction methods are essential to prevent postoperative CSF leakage. Although collagen matrix has been applied for dural reconstruction in neurosurgery, its suitability for application in extended eTSS remains unclear. Eighteen patients underwent modified shoelace dural closure using collagen matrix after lesionectomy via extended eTSS. In this technique, a collagen matrix, which was placed subdurally (inlay graft), was continuously sutured with both open dural edges like a shoelace. Then, another collagen matrix was placed epidurally (onlay graft), and rigid reconstruction was performed using the septal bone and a resorbable fixation mesh. Postoperative CSF leakage did not occur in 17 patients but did occur in 1 patient with tuberculum sellae meningioma. In this case, the CSF leakage point was detected just around the area between the coagulated dura and the adjacent collagen matrix. The collagen matrix harvested from this area was pathologically examined; neovascularization and fibroblastic infiltration into the collagen matrix were not detected. On the other hand, neovascularization and fibroblast infiltration into the collagen matrix were apparent on the surface of the collagen matrix harvested from the non-CSF leakage area. Our novel dural closure technique using collagen matrix could be an effective option for sellar reconstruction in extended eTSS; however, it should be applied in patients in whom normal dural edges are preserved.

A novel endoscopic ventriculocisternostomy and stenting technique with a transparent acryl puncture needle for a trapped temporal horn: a technical report and literature review.

Trapped temporal horn is a rare type of noncommunicating focal hydrocephalus, and no standard treatment has been established yet for trapped temporal horn. Recent studies have shown the efficacy of endoscopic ventriculocisternostomy by opening the choroidal fissure; however, some surgical complications were reported during the procedure. Thus, we aimed to report a novel endoscopic ventriculocisternostomy and stenting technique for trapped temporal horn. In this technique, a 5.8-mm transparent acryl puncture needle with a 2.7-mm 0° rigid endoscope was used to open the choroidal fissure. It can fenestrate the choroidal fissure under real-time endoscopic observation of the critical neurovascular structures over the choroidal fissure. Moreover, the dull tip of the needle is less likely to injure the critical neurovascular structures, resulting in safer ventriculocisternostomy than the previously reported technique. Then, a stent is placed along the tract to prevent future obstruction of the stoma. Six trapped temporal horns in four patients were treated using the technique. All the patients showed improved symptoms with no surgical complications. None of the patients showed recurrence of trapped temporal horn during the mean follow-up period of 39.3 months. The combination of endoscopic ventriculocisternostomy and stenting with a transparent acryl puncture needle is a safe and effective treatment option for trapped temporal horn.

Novel Endoscopic Technique for Inserting a Sheath into a Slit Ventricle: The Water-Slide Technique.

BACKGROUND: The efficacy and safety of endoscopic procedures for slit ventricle syndrome (SVS) have been presented in recent studies. However, inserting a sheath into a target ventricle is essential in the beginning of endoscopic procedures for SVS, and this maneuver is challenging owing to the quite narrow ventricular space. We report a novel flexible endoscopic technique, the water-slide technique, that can effectively guide a sheath into a slit ventricle without the use of other adjunctive devices, such as a neuronavigation system and an ultrasound machine. METHODS: Ten endoscopic procedures using the water-slide technique were performed in 9 patients with SVS. All patients had undergone ventriculoperitoneal shunt placement. Using the technique, the sheath was first placed on the flexible endoscope. The endoscope was then inserted into the lateral ventricle along the tract around the pre-existing ventricular catheter with irrigation of artificial cerebrospinal fluid via the working channel of the endoscope. After the endoscope reached the ventricle, the sheath was inserted into the ventricle along the endoscope. The endoscope was then used as a stylet. The endoscopic procedure was performed afterward. Continuous irrigation of artificial cerebrospinal fluid via the working channel is important when using this technique. RESULTS: In all cases, the sheath was successfully introduced to the slit ventricle without the use of adjunctive devices. There were no postoperative complications correlated with the maneuver. CONCLUSIONS: This novel endoscopic technique is effective and safe for inserting a sheath into a target ventricle in the management of SVS.

[Retrospective analysis of nosocomial COVID-19: a comparison between patients with hematological disorders and other diseases].

Nosocomial coronavirus disease 2019 (COVID-19) had occurred at our hospital. We retrospectively analyzed the differences between patients with nosocomial COVID-19 and either hematological disease (n=40) or other diseases (n=57). The analysis was completed within 60 days for surviving patients. Among the patients with hematological disease and those with other diseases, there were 21 (52.5%) and 20 (35.1%) deaths, respectively. Although the patients with hematological disease received favipiravir more frequently than patients with other diseases (21 [52.5%] vs. 15 [35.3%], respectively; P<0.05), their median overall survival was poor (29 days; P=0.078). Furthermore, the median duration from oxygen therapy initiation to death or intubation was significantly shorter in the patients with hematological disease (5 days [range, 1-17 days] vs. 10 days [1-24 days], respectively; P<0.05). Furthermore, the patients with hematological disease and nosocomial COVID-19 exhibited more marked respiratory failure and poorer outcomes leading to death in a shorter time period than the patients with other diseases and nosocomial COVID-19.

Fully Endoscopic Transcylinder Trans-Magendie Foraminal Approach for Fourth Ventricular Cavernoma: A Technical Case Report.

BACKGROUND: Neuroendoscopy offers wide and close surgical views with fine illumination, even in deep surgical sites. Furthermore, transcylinder surgery has the advantage that a tubular retractor can protect critical neurovascular structures in the surgical corridor. These advantages of neuroendoscopy and transcylinder surgery can contribute to safer and less invasive surgical approaches for deep-seated fourth ventricular lesions, for which various critical neurovascular structures exist along the surgical route. CASE DESCRIPTION: A 54-year-old man with a fourth ventricular cavernoma underwent tumor resection via the endoscopic transcylinder trans-Magendie foraminal approach. A 6.8-mm transparent sheath (cylinder) was introduced into the fourth ventricle via the foramen of Magendie without incisions in the inferior medullary velum or the tela choroidea, resulting in the minimal retraction of and trauma to critical neurovascular structures in the surgical corridor. Under the view of a 2.7-mm rigid neuroendoscope, the lesion was completely removed with preservation of a venous anomaly on the ventral side of the aqueduct of Sylvius. Neuroendoscopy could offer a fine surgical view even under continuous irrigation with artificial cerebrospinal fluid; it prevented collapse of the fourth ventricle and facilitated anatomic understanding by the surgeons. The postoperative course was uneventful. CONCLUSIONS: Our novel approach can be an effective surgical option for fourth ventricular lesions with minimal cerebellar retraction and injury.

Feasibility and Safety of Sac Embolization Using N-Butyl Cyanoacrylate in Emergency Endovascular Aneurysm Repair for Ruptured Abdominal Aortic Aneurysms or Isolated Iliac Artery Aneurysms.

PURPOSE: To evaluate the feasibility and safety of sac embolization with N-butyl cyanoacrylate (NBCA) in emergency endovascular aneurysm repair (EVAR) for ruptured abdominal aortic aneurysm (AAA) and iliac artery aneurysm (IAA) in comparison to EVAR without sac embolization. MATERIALS AND METHODS: Between February 2012 and December 2019, among 44 consecutive patients with ruptured AAA or IAA, 29 underwent EVAR. Of these, 22 patients (median age 77.5 years; 18 men) had concomitant sac embolization using NBCA; the remaining 7 patients (median age 88 years; 6 men) underwent EVAR without sac embolization and form the control group. The technical success, clinical success (hemodynamic stabilization), procedure-related complications, and mortality were compared between the groups. RESULTS: All EVAR procedures and embolizations were successful. The clinical success rates in the NBCA and control groups were 95% (21/22) and 71% (5/7), respectively (p=0.14). There was no complication related to the procedure. Type II endoleak occurred in 4 of 21 patients (19%) in the NBCA group vs none of the control patients. One patient (5%) died in the NBCA group vs 3 (43%) in the controls (p=0.034). CONCLUSION: Sac embolization using NBCA in emergency EVAR appears to be feasible and safe for ruptured AAA and IAA.

[A Case of Pediatric C1 Dysplasia with Ruptured Aneurysm in Collateral Plexiform Arterial Network].

A 3-year-old girl was admitted to our hospital with symptoms including headache, nausea, and vomiting. Head CT scan showed subarachnoid hemorrhage in the right carotid cistern. Digital subtraction angiography revealed right internal caortid artery(ICA)malformation at the C1 segment with collateral plexiform arterial network. The right ICA branched into posterior communicating artery and anterior choroidal artery(AChoA)and the ICA was decreased in caliber. The distal portion of the C1 segment of the ICA continued to the collateral plexiform arterial network, forming a saccular aneurysm. The plexiform arterial network connected to the right AChoA and the anterior communicating artery and continued to the distal portion of the right M1 segment. Right cervical carotid artery was normal. There was no transdural collateral flow from the right external carotid artery. Genetic analysis of a variant of RING finger protein 213 was negative. We diagnosed this patient with C1 dysplasia. We performed coil embolization for the aneurysm. The patient was discharged without any neurological deficit. Four months after the surgery, recurrence of the aneurysm was observed. We suspected that the aneurysm was formed due to hemodynamic mechanism and vulnerability of the collateral plexiform arterial network.

Is TEVAR with Full Petticoat Technique Effective for Complicated Acute Type B Dissection Cases?

Treatment by thoracic endovascular aortic repair (TEVAR) for type B dissection has improved outcomes. We tried the procedure named "Full Petticoat technique" in which the proximal entry tear was excluded with a covered stent and extended bare metal stents were placed to the aortic bifurcation for three complicated type B dissection cases with dynamic obstruction of the common iliac artery. Follow-up computed tomography revealed favorable aortic remodeling in which the true lumen was expanded. The short-term result of this procedure has shown acceptable aortic remodeling. The significance of this procedure is still unknown in the long term; hence long-term follow-up is necessary to completely understand the usefulness of this technique.

Evaluation of method bias for determining bacterial populations in bacterial community analyses.

Various methods are used for analyzing a bacterial community. We recently developed a method for quantifying each bacterium constituting the microbiota by combining a next-generation sequencing (NGS) analysis with a quantitative polymerase chain reaction (NGS-qPCR) assay. Our NGS-qPCR method is useful for analyzing a comprehensive bacterial community because it is enables the easy calculation of the amounts of each bacterium constituting the microbiota. However, it has not been confirmed whether the estimated bacterial community obtained using this NGS-qPCR method corresponds to the results obtained using conventional methods. Accordingly, we prepared model bacterial community samples and analyzed them by several methods (NGS-qPCR, species-specific qPCR, flow cytometry, total direct counting by epifluorescent microscopy [TDC], and plate count). The total bacterial cell densities determined by the PCR-based methods were largely consistent with those determined by the TDC method. There was a difference between the amounts of each bacterium analyzed by NGS-qPCR and species-specific qPCR, although the same trend was shown by both species-specific qPCR and NGS-qPCR. Our findings also demonstrated that there is a strong positive correlation between the cell densities of a specific bacterial group in craft beer samples determined by group-specific qPCR and NGS-qPCR, and there were no significant differences among quantification methods (we tested two bacterial groups: lactic acid bacteria and acetic acid bacteria). Thus, the NGS-qPCR method is a practical method for analyzing a comprehensive bacterial community based on a bacterial cell density.

Sake yeast YHR032W/ERC1 haplotype contributes to high S-adenosylmethionine accumulation in sake yeast strains.

Sake yeasts are ideally suited for sake making, producing higher levels of ethanol, proliferating at lower temperatures, and producing greater levels of various aromatic components and nutrients than laboratory yeasts. To elucidate the mechanism underlying S-adenosylmethionine (SAM) accumulation in sake yeast strains compared with that in laboratory yeast strains, we performed quantitative trait locus (QTL) analysis and identified a significant QTL on chromosome VIII. Of the 165 genes mapped at 49.8 cM from the left-end DNA marker of chromosome VIII, we focused on the YHR032W/ERC1 gene, encoding a member of the multi-drug and toxin extrusion family having antiporter activity and involved in SAM accumulation and ethionine resistance. Expression of the sake yeast ERC1 haplotype (K7ERC1) in a low- and high-copy number plasmid BYΔerc1 resulted in intracellular SAM accumulation, whereas expression of the laboratory yeast ERC1 haplotype (XERC1) did not. Comparison between DNA sequences of K7ERC1 and XERC1 revealed three amino acid substitutions: S51N, V263I, and N545I. Site-directed mutagenesis revealed that the N545I frameshift mutation was responsible for the K7ERC1 phenotype. These results indicate that K7ERC1 contributes to SAM accumulation in sake yeast strains.

Late Sac Behavior after Endovascular Aneurysm Repair for Abdominal Aortic Aneurysm.

BACKGROUND: Sac behavior after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAAs) is considered as a surrogate for the risk of late rupture. The purpose of the study is to assess the sac behavior of AAAs after EVAR. METHODS AND RESULTS: Late sac enlargement (LSE) (≥5 mm) and late sac shrinkage (LSS) (≥5 mm) were analyzed in 589 consecutive patients who were registered at 14 national centers in Japan. The proportions of patients who had LSE at 1, 3 and 5 years were 2.6% ± 0.7%, 10.0% ± 1.6% and 19.0% ± 2.9%. The proportions of patients who had LSS at 1, 3 and 5 years were 50.1% ± 0.7%, 59.2% ± 2.3% and 61.7% ± 2.7%. Multiple logistic regression analysis identified two variables as a risk factor for LSE; persistent endoleak (Odds ratio 9.56 (4.84-19.49), P <0.001) and low platelet count (Odds ratio 0.92 (0.86-0.99), P = 0.0224). The leading cause of endoleak in patients with LSE was type II. CONCLUSIONS: The incidence of LSE is not negligible over 5 year period. Patients with persistent endoleak and/or low platelet count should carefully be observed for LSE. CLINICAL TRIAL REGISTRATION: UMIN-CTR (UMIN000008345).