Simultaneous medial closing wedge distal femoral varus osteotomy and double-bundle anterior cruciate ligament reconstruction in the symptomatic femoral valgus deformity: A case report.

Distal femoral varus osteotomy (DFVO) is a widely recognized surgical procedure used to address valgus malalignment in patients with knee joint disorders. However, it still remains unclear whether anterior cruciate ligament (ACL) reconstruction can be performed in a single procedure along with DFVO. Herein, we present a 73-year-old female patient who developed lateral osteoarthritis of the knee with valgus alignment due to chronic ACL deficiency following a twisting injury during skiing. She was physiologically very active, and strongly demanded to return to sports. We performed a combined procedure involving a medial closing wedge DFVO using an anatomical locking plate, along with double-bundle ACL reconstruction. The postoperative radiograph confirmed successful correction of knee alignment, specifically achieving varus alignment with precise conformance of the anatomical plate to the medial contour of the distal femur following the osteotomy. The patient resumed her previous sports activities without experiencing knee pain. The operated knee demonstrated restored anterior stability, as indicated by negative Lachman test results, and regained full range of motion. Both the Knee Injury and Osteoarthritis Outcome Score and the 2011 Knee Society score demonstrated continuous postoperative improvements over the three-year follow-up period, indicating positive functional outcomes and joint preservation. To the best of our knowledge, this is the first case of medial closing wedge DFVO with anatomic double-bundle ACL reconstruction in the symptomatic femoral valgus deformity with chronic ACL deficiency in the literature.

Development of an automatic surgical planning system for high tibial osteotomy using artificial intelligence.

BACKGROUND: This study proposed an automatic surgical planning system for high tibial osteotomy (HTO) using deep learning-based artificial intelligence and validated its accuracy. The system simulates osteotomy and measures lower-limb alignment parameters in pre- and post-osteotomy simulations. METHODS: A total of 107 whole-leg standing radiographs were obtained from 107 patients who underwent HTO. First, the system detected anatomical landmarks on radiographs. Then, it simulated osteotomy and automatically measured five parameters in pre- and post-osteotomy simulation (hip knee angle [HKA], weight-bearing line ratio [WBL ratio], mechanical lateral distal femoral angle [mLDFA], mechanical medial proximal tibial angle [mMPTA], and mechanical lateral distal tibial angle [mLDTA]). The accuracy of the measured parameters was validated by comparing them with the ground truth (GT) values given by two orthopaedic surgeons. RESULTS: All absolute errors of the system were within 1.5° or 1.5%. All inter-rater correlation confidence (ICC) values between the system and GT showed good reliability (>0.80). Excellent reliability was observed in the HKA (0.99) and WBL ratios (>0.99) for the pre-osteotomy simulation. The intra-rater difference of the system exhibited excellent reliability with an ICC value of 1.00 for all lower-limb alignment parameters in pre- and post-osteotomy simulations. In addition, the measurement time per radiograph (0.24 s) was considerably shorter than that of an orthopaedic surgeon (118 s). CONCLUSION: The proposed system is practically applicable because it can measure lower-limb alignment parameters accurately and quickly in pre- and post-osteotomy simulations. The system has potential applications in surgical planning systems.

Exploration of postural effects on the external jugular and diploic venous system using upright computed tomography scanning.

PURPOSE: Few studies have investigated the influence of posture on the external jugular and diploic venous systems in the head and cranial region. In this study, we aimed to investigate the effects of posture on these systems using upright computed tomography (CT) scanning. METHODS: This study retrospectively analysed an upright CT dataset from a previous prospective study. In each patient, the diameters of the vessels in three external jugular tributaries and four diploic veins were measured using CT digital subtraction venography in both supine and sitting positions. RESULTS: Amongst the 20 cases in the original dataset, we eventually investigated 19 cases due to motion artifacts in 1 case. Compared with the supine position, most of the external jugular tributaries collapsed, and the average size significantly decreased in the sitting position (decreased by 22-49% on average). In contrast, most of the diploic veins, except the occipital diploic veins, tended to increase or remain unchanged (increased by 12-101% on average) in size in the sitting position compared with the supine position. However, the changes in the veins associated with this positional shift were not uniform; in approximately 5-30% of the cases, depending on each vein, an opposite trend was observed. CONCLUSION: Compared to the supine position, the contribution of external jugular tributaries to head venous drainage decreased in the sitting position, whilst most diploic veins maintained their contribution. These results could enhance our understanding of the physiology and pathophysiology of the head region in upright and sitting positions.

Aneurysmal subarachnoid hemorrhage occurring during sleep: Clinical characteristics and risk factors.

BACKGROUND: Aneurysmal subarachnoid hemorrhage (aSAH) is known to be triggered by several specific human activities. Sleep, by contrast, has not been considered a triggering activity for aSAH, and clinical characteristics of patients who sustain aSAH during sleep have rarely been reported in the literature. METHODS: This is a retrospective analysis on the data acquired through a multicenter aSAH registry. Between January 2019 and December 2021, a total of 732 aSAH patients had been registered into our database. After excluding 109 patients whose activities at aSAH onset had been unidentifiable, the remaining 623 aSAH patients were dichotomized to 59 patients who sustained aSAH during sleep (Sleep group) and 564 patients who sustained aSAH during daytime activities (Awake group). Two-group comparison of demographic variables and multivariate logistic regression analysis were performed to clarify their clinical characteristics and identify potential risk factors. RESULTS: The Sleep group exhibited significantly higher frequencies of diabetes (15.5 % vs. 6.4 %, p = 0.01) and antiplatelet use (13.8 % vs. 4.6 %, p=0.004) than the Awake group. Furthermore, multivariate logistic regression analysis showed that diabetes (OR, 3.051; 95 % CI, 1.281-7.268; p = 0.012) and antiplatelet use (OR, 3.640; 95 % CI, 1.422-9.316; p = 0.007) were correlated with aSAH occurring during sleep. There were no significant inter-group differences in the patient outcomes evaluated at discharge. CONCLUSION: The current results indicate that risk factors may exist for aSAH occurring during sleep. Further investigations on how comorbidities such as diabetes, antiplatelet use and sleep apnea affect human hemodynamic and hemostatic parameters during sleep is warranted to better understand those relationships.

Bridging veins at the craniocervical junction: from anatomy to clinical significance in dural arteriovenous shunts.

PURPOSE: Bridging veins (BVs) serve as a route of pial venous reflux, and its anatomy is essential to understand the pathophysiology of dural arteriovenous shunts (dAVSs) around the craniocervical junction (CCJ) (from the jugular foramen level to the atlantal level). However, the anatomical variations of the BVs and their proximal connections remained poorly elucidated. This study aimed to radiologically investigate the anatomy of the bridging veins around CCJ and discuss the clinical significance of these BVs in the dAVS. METHODS: We investigated normal venous anatomy of the BVs from the jugular foramen level to the atlantal level using preoperative computed tomography digital subtraction venography in patients undergoing elective neurosurgery. BVs affected by the dAVSs in the same region were also evaluated. The three types of dAVS, craniocervical junction, anterior condylar, and proximal sigmoid sinus, were investigated. RESULTS: We identified six BV groups: superolateral, anterolateral, lateral, posterior, inferolateral, and inferoposterior. The superolateral and inferolateral groups, connected with the proximal sigmoid sinus and suboccipital cavernous sinus, respectively, were the largest groups. Each group has a specific downstream venous connection. The association with dVASs was observed only in the inferolateral group, which was typically the sole venous drainage in most dAVSs at the CCJ. CONCLUSION: We reported detailed anatomy of BVs from the jugular level to the atlantal level, which enhanced our understanding of the pathophysiology of dAVSs in the corresponding region.

A Case of Neurofibromatosis Type 1 Diagnosed after Idiopathic Rupture of Superficial Temporal Artery Pseudoaneurysm Requiring Endovascular Treatment.

Patients with neurofibromatosis type 1 not only have characteristic skin findings but are also known to have vascular disorders due to vascular vulnerability. A 44-year-old man with previously undiagnosed neurofibromatosis type 1 was brought to the emergency room due to a sudden subcutaneous hematoma with no history of trauma. Angiography revealed extravasation from the parietal branch of the right superficial temporal artery, which was embolized with n-butyl-2-cyanoacrylate. However, the next day, the patient exhibited an increased subcutaneous hematoma, and new extravascular leakage was detected at the frontal branch of the superficial temporal artery, which was also embolized with n-butyl-2-cyanoacrylate. The patient had physical findings characteristic of neurofibromatosis type 1, such as café-au-lait spots, and was subsequently diagnosed with neurofibromatosis type 1. No obvious neurofibroma or any other subcutaneous lesion associated with neurofibromatosis type 1 was identified in the affected area. Massive idiopathic arterial bleeding in the scalp, although infrequent, can be fatal. Neurofibromatosis type 1 should be considered when a subcutaneous scalp hematoma is observed without a history of trauma, even if the facial skin structure appears normal. Neurofibromatosis type 1 is also known to have multiple sources of hemorrhage. Thus, it is important to repeatedly evaluate vascular structures via cerebral angiography, contrast-enhanced computed tomography, and magnetic resonance imaging, if necessary.

"Missing-piece" sign with dural arteriovenous fistula at craniocervical junction: A case report.

OBJECTIVES: Spinal dural arteriovenous fistula (sDAVF) is a rare and often underdiagnosed spinal disease. Early diagnosis is required because the deficits are reversible and delays in treatment cause permanent morbidity. Although the abnormal vascular flow void is a critical radiographic feature of sDAVF, they are not always present. A characteristic enhancement pattern of sDAVF has been recently reported as the "missing-piece" sign which can lead to the early and correct diagnosis. METHODS: We presented imaging findings, treatment decisions, and the outcome of a rare case of sDAVF, in which the "missing-piece" sign appeared atypical. RESULTS: A 60-year-old woman developed numbness and weakness in her extremities. Spinal MRI revealed longitudinal hyperintensity in the T2-weighted image, extending from the thoracic level to medulla oblongata. At first, myelopathy with inflammation or tumor was suspected because of the lack of flow voids and vascular abnormalities in CT-angiography and MR-DSA. However, we administered intravenous methylprednisolone and her symptom got worse with the appearance of the "missing-piece" sign. Then, we successfully diagnosed sDAVF by angiography. The "missing-piece" sign was considered to derive from inconsistency of the intrinsic venous system of spinal cord, with the abrupt segments without enhancement. The same etiology was considered in our case. CONCLUSIONS: Detecting the "missing-piece" sign can lead to the correct diagnosis of sDAVF, even if the sign appeared atypical.

Prognostic significance of preoperative neutrophil-to-lymphocyte ratio in surgically resected schwannomas.

Objective: The goal of schwannoma resection is to control the tumor while preserving neurological function. Schwannomas have a variable postoperative growth pattern, therefore preoperative prediction of a schwannoma's growth pattern is favorable. This study aimed to examine the relationship between preoperative neutrophil-to-lymphocyte ratio (NLR) and postoperative recurrence and retreatment in patients with schwannoma. Methods: We retrospectively examined 124 patients who underwent schwannoma resection in our institution. Associations between preoperative NLR, other patient and tumor characteristics, and tumor recurrence and retreatment were analyzed. Results: Median follow-up was 2569.5 days. Postoperative recurrence occurred in 37 patients. Recurrence that required retreatment occurred in 22. Treatment-free survival (TFS) was significantly shorter in patients with NLR ≥2.21 (P = 0.0010). Multivariate Cox proportional hazards regression showed that NLR and neurofibromatosis type 2 were independent predictors of retreatment (P = 0.0423 and 0.0043, respectively). TFS was significantly shorter in patients with NLR ≥2.21 in the following subgroups: sporadic schwannoma, primary schwannoma, schwannoma ≥30 mm in size, subtotal resection, vestibular schwannoma, and postoperative recurrence. Conclusions: Preoperative NLR ≥2.21 before surgery was significantly associated with retreatment after schwannoma resection. NLR may be a novel predictor of retreatment and assist surgeons in preoperative surgical decision making.

Role of endovascular treatment for ruptured aneurysms involving the anterior spinal artery at the craniocervical junction.

Ruptured aneurysms at the craniocervical junction (CCJ) involving the anterior spinal artery (ASA) are rare and consist of heterogenous lesions with variable clinical entities. However, the standard therapeutic strategy for the lesions has not been well-established. Moreover, despite advances in modern neurointervention, reports describing endovascular treatment for this specific lesion have been few. Here, we report three cases of ruptured aneurysms on the pial tributary of the ASA at the CCJ, which were subsequently treated by transarterial glue injection or coil embolization. Endovascular treatment can be a therapeutic option, particularly for these ruptured aneurysms. Either transarterial glue injection or coil embolization can be effective depending on the type of etiology and the surrounding vasculature anatomy.

Similar short-term KOOS between open-wedge high tibial osteotomy and total knee arthroplasty in patients over age 60: A propensity score-matched cohort study.

OBJECTIVES: The purpose of the present study was to evaluate improvement in the Knee Injury and Osteoarthritis Outcome Score (KOOS) after open-wedge high tibial osteotomy (HTO) in comparison with total knee arthroplasty (TKA) in cohorts over age 60 matched by pre-operative age, gender, body mass index (BMI), hip-knee-ankle angle (HKAA), KOOS sub-scores, and osteoarthritis (OA) grade. METHODS: Propensity score matching was performed between 162 HTO patients and 134 TKA patients. When calculating the propensity score by multivariate logistic regression analysis, the following pre-operative confounders were included: age, gender, BMI, HKAA, KOOS sub-scores, and OA grade. Consequently, a total of 55 patients were included in each group. The Student's t-test was used to analyse differences in the post-operative KOOS sub-scores between groups. RESULTS: After propensity score matching, all matched pre-operative valuables were identical, with no significant differences between the HTO and TKA groups. None of the post-operative KOOS sub-scores at 1 year after surgery showed a significant difference between the HTO and TKA groups. Both groups demonstrated significant and comparable post-operative improvement in every KOOS sub-score. CONCLUSIONS: In patients over age 60, there was no significant difference in short-term pain relief and improvements in activity and quality of life between HTO and TKA after propensity score matching including pre-operative age, KOOS sub-scores, and OA grade. HTO is a joint preservation procedure that is valid for knee OA even in individuals over age 60.

Targeted embolisation for coexisting conus medullaris arteriovenous malformation and cauda equina arteriovenous fistulas with a varix on a shared drainer†.

BACKGROUND: The coexistence of vascular malformations in the conus medullaris and cauda equina has been rarely reported, and the complex angioarchitecture in multiple arteriovenous lesions remains poorly understood. CASE DESCRIPTION: A 17-year-old woman presented with a sudden-onset, stepwise worsening of weakness and pain in the bilateral legs. Angiography revealed conus medullaris arteriovenous malformation and cauda equina arteriovenous fistulas. One of the drainers was shared between the coexisting lesions and harboured a varix. Targeted embolisation of a fistulous point in the conus lesion was performed with precaution to prevent occluding the common drainage route, which led to symptom improvement with angiographical diminishment of the varix. CONCLUSIONS: Recognising that communications between drainers can be observed in multiple spinal arteriovenous lesions is important in facilitating a safe embolisation. Cautious assessment of angiogram with fusion images of cone-beam computed tomography and volumetric T2 magnetic resonance imaging can help in establishing the diagnosis and treatment strategy.

A case of refractory chronic subdural hematoma and internal carotid artery stenosis sequentially treated with surgical drainage, middle meningeal artery embolization, and carotid artery stenting.

Background: Both chronic subdural hematoma (CSDH) and ischemic cerebrovascular disease are commonplace in the clinical context, and their combination is sometimes experienced. We describe a unique and challenging case in which both therapeutic interventions were indispensable and performed in a sequential manner. This report aims to discuss the management of hemorrhagic and ischemic conditions where CSDH and carotid artery stenosis coexist. Case Description: An 83-year-old male presented with the left cerebral infarction due to the left internal carotid artery (ICA) stenosis. The coexisting left CSDH was surgically drained first. Then, the left middle meningeal artery (MMA) was endovascularly embolized to prevent hematoma recurrence under antiplatelet therapy, before the left carotid artery stenting (CAS) was successfully conducted. The subdural hematoma gradually grew but remained asymptomatic. However, he later presented with another stroke due to the progressive right ICA stenosis that had been conservatively treated initially. Emergency right CAS was required eventually. Conclusion: Under the circumstances where CSDH is present but antiplatelet therapy is inevitable, MMA embolization could be a reasonable treatment option to avoid additional surgical procedures. Furthermore, early intervention should be considered even for asymptomatic carotid stenosis in terms of shortening the administration period of antiplatelet agents.

Extracranial prevertebral venous network of the craniocervical junction: CT-digital subtraction venography analysis.

PURPOSE: Although the craniocervical junction has a complex anatomical structure associated with clinical diseases, its ventral venous network has not been well studied. This study aimed to clarify the extracranial ventral venous structure at the craniocervical junction. METHODS: Head computed tomography digital subtraction venography (CT-DSV) images of 273 patients (age 6 months to 93 years) taken at our department were retrospectively analyzed. We analyzed the frequency and anatomical features of the venous channels, as well as their upstream and downstream connections with the surrounding channels at the ventral craniocervical junction, from the level of the hypoglossal canal to the second cervical vertebra. RESULTS: In 54% of the cases, the vein descended from the anterior condylar confluence, running medially along the basioccipital and fusing with its counterpart in the midline at the level of the atlanto-occipital membrane. Furthermore, 24% of this vein was connected caudally to the anterior external vertebral venous plexus. We also identified venous channels, either as a sole vein or venous plexus, on the tip of the odontoid process (10%), which has not been well described previously. The vein around the odontoid process was connected to several veins, including the aforementioned vein anterior to the condyle and the anterior internal vertebral venous plexus. CONCLUSIONS: CT-DSV analysis revealed a detailed venous architecture ventral to the craniocervical junction. Venous structures identified in this study may be involved in diseases in this area.

Tibial Condylar Valgus Osteotomy Combined With Medial Open-Wedge Distal Tuberosity Tibial Osteotomy.

Severe varus deformity in osteoarthritic knees is attributed not only to bony deformity but also to intra-articular deformity as a result of medial joint space narrowing with lateral joint space widening (increased joint line convergence angle). In such knees, correction of bony deformity by high tibial osteotomy (HTO) alone may not be capable of restoring physiological joint geometry and biomechanics. Tibial condylar valgus osteotomy (TCVO), an L-shaped osteotomy in the medial tibial condyle, has been proposed to improve articular stability and congruity by elevating the medial tibial joint line and addressing the articular component of the deformity; however, its surgical efficacy for correction of the valgus deformity is limited. Therefore a procedure combining HTO and TCVO can be a reasonable option to achieve restoration of the knee joint physiology in such situations. In our current practice, medial open-wedge distal tuberosity tibial osteotomy (MOW-DTO) has been the procedure of primary option among the HTO procedures to avoid patellofemoral overload which could be an inherent problem in medial open-wedge HTO. In this article, the surgical rationale and the combined procedure of TCVO and MOW-DTO are described.

Combined transarterial and transvenous embolization of multi-hole pial arteriovenous fistula with large varix.

BACKGROUND: Pial arteriovenous fistula (AVF) is a vascular fistulous disease in which the cerebral pial artery and vein are directly connected without the intervening nidus within a sub-pial space. Multi-hole pial AVFs, wherein multiple feeders flow into one drainer, are usually formed with complex angioarchitecture and are difficult to treat. METHODS: A rare case of an adult patient with hereditary hemorrhagic telangiectasia and multi-hole pial AVF was described. A 23-year-old woman was referred to our hospital. She was previously diagnosed with left cerebellar pial AVF with multiple feeders (bilateral superior cerebellar artery and common trunk of the left anterior inferior cerebellar artery and posterior inferior cerebellar) and large varix that had been untreated for 9 years. The enlargement of the large varix with the new second varix formation was revealed by angiography. Although asymptomatic, considered to be a risk for future hemorrhage was the continuous high hemodynamic stress. RESULTS: Endovascular embolization was performed by securing safe transarterial n-butyl-2-cyanoacrylate injection by transarterial and transvenous coil placement to the shunt points and feeders, resulting in total occlusion of the fistula without any complications. Extensive transvenous coil placement inside the varix allowed safe embolization of the entire fistula with multiple high-flow feeders. Moreover, bidirectional (transarterial and transvenous) retrograde coil embolization enabled firm obliteration of the shunt points. CONCLUSIONS: Performing combined transarterial and transvenous embolization in a well-balanced manner was considered to treat multi-hole pial AVF to provide a safe and effective embolization.

Imaging of the venous plexus of Rektorzik using CT-digital subtraction venography: a retrospective study.

PURPOSE: The venous plexus of Rektorzik (VPR), first described by Rektorzik in 1858, is a venous plexus around the internal carotid artery in the carotid canal. However, the VPR has never been investigated using the recently developed imaging modalities. In this study, we analyzed the VPR using computed tomography-digital subtraction venography (CT-DSV). METHODS: This study included 253 patients who had undergone head CT-DSV. The presence or absence of the right and left VPRs and their connecting veins were visually examined by two researchers. RESULTS: The VPR was observed in 60 patients (24%), 39 of which showed VPR only on the right side, 10 only on the left side, and 11 on both sides. VPR was significantly more common on the right side (p = 0.0002) and was observed more frequently around the horizontal segment of the internal carotid artery than around the vertical segment. The most common veins identified as distal and proximal VPR connections were the cavernous sinus (63/71, 89%) and the anterior condylar confluence (27/71, 38%), respectively. The mean age was significantly lower in patients with the VPR than in those without (53 vs. 57 years, p = 0.02). CONCLUSION: The VPR was significantly more frequent on the right side and in younger patients but was not a radiographically constant structure. In most cases, the VPR connected the cavernous sinus and anterior condylar confluence. Preoperative evaluation of VPR may lead to refined surgical procedures.

Carotid body tumor with neck metastasis due to germline SDHB variant: a case report and literature review.

Carotid body tumor involving the succinate dehydrogenase subunit B (SDHB) variant reportedly had a higher frequency of metastasis than other variants of succinate dehydrogenase. However, the correlation between genotype and phenotype among patients with carotid body tumor with SDHB gene variant remains unclear. Thus, we present a case of carotid body tumor with neck lymph metastasis caused by a novel SDHB variant, which resulted in long-term disease-free survival achieved after surgery. A 43-year-old man presented to our hospital with a 2-year history of a painless neck mass. Based on the radiographic findings, the patient was diagnosed with carotid body tumor with a possible Shamblin type III tumor. Another mass was detected and suspected to be a lymph node metastasis. The patient underwent resection of the tumor and lymph nodes. The common carotid artery, internal carotid artery, external carotid artery, internal jugular vein, vagal nerve, and hypoglossal nerve were resected with the tumor. Histopathological examination revealed a paraganglioma. The histological findings of the lymph nodes were similar to those of the carotid body tumor and were confirmed to be metastases of paraganglioma. To analyze the germline SDHx variant, a nonsense variant was detected in the SDHB gene at exon 2, c. 136C > T, p. Arg46*. During the follow-up 80 months after surgery, the patient exhibited no signs of recurrence, metastasis, or development of paragangliomas in other organs. This was the first case of carotid body tumor accompanied by neck metastasis caused by a germline nonsense SDHB variant at exon 2, c. 136C > T, p. Arg46*. Carotid body tumor with neck lymph metastasis caused by this nonsense variant could achieve long-term disease-free survival after surgery. Gene analysis, including SDHB variant, should be performed to predict the prognosis and future risk of metastasis. Genetic testing of SDHB may give a crucial information for the treatment and follow-up strategies of carotid body tumor. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13691-021-00522-x.

Stepwise improvement in limb shaking achieved by staged angioplasty for severe carotid stenosis.

Cerebral hyperperfusion syndrome is a rare but severe complication of carotid artery stenting or carotid endarterectomy. Staged angioplasty is reportedly an effective strategy to avoid cerebral hyperperfusion syndrome. We encountered a case of internal carotid artery stenosis with a rare clinical presentation of limb shaking that was successfully improved by staged angioplasty. To our knowledge, there are no reported cases of limb shaking treated with staged angioplasty.A 76-year-old woman presented with continuous chorea in her left lower limb and shoulder. Medical examination revealed a tiny cerebral infarction in the right corona radiata and severe right internal carotid artery stenosis. Angiography showed near occlusion of the right internal carotid artery. Staged angioplasty was performed to avoid the risk of cerebral hyperperfusion syndrome. The first angioplasty resulted in an expanded diameter of 2.5 mm and was followed by definitive carotid artery stenting using a closed-cell stent 3.5 weeks later. Limb shaking improved in a stepwise manner along with an improvement in internal carotid artery stenosis and distal flow state with no signs of cerebral hyperperfusion syndrome. Patients with internal carotid artery stenosis or occlusion presenting with limb shaking have been suggested to have impaired cerebrovascular reactivity, which is also thought to be a risk factor for cerebral hyperperfusion syndrome. The stepwise improvement in limb shaking observed in this case supports the idea that the pathophysiology of limb shaking is related to cerebral haemodynamic impairment. Measures to prevent cerebral hyperperfusion syndrome, including staged angioplasty, should be actively considered in patients with limb shaking because the symptoms themselves suggest severe hypoperfusion.

Biomechanical analysis of the role of hinge support fixators on hinge stability in medial closing wedge distal femoral osteotomy.

BACKGROUND: This study aimed to examine the hinge-stabilizing biomechanical effects of hinge support fixators, applied for lateral hinge fractures sustained following distal femoral osteotomy. METHODS: Medial closing wedge distal femoral osteotomy was performed using a locking plate on 10 cadaveric limbs. The limbs were divided into two groups: the non-fracture group and the lateral hinge fracture group. A cyclic axial load of 400 N was applied to the knee to keep it extended and flexed at 45°. The hinge-stabilizing effects of adding a screw or a short support plate to the lateral fracture site were examined by measuring the translation and rotational angles of the anterodistal and posterodistal hinge positions as well as the surface strains of the medial locking plate. FINDINGS: Translation and rotation in the fracture group were significantly more pronounced than in the non-fracture group, at the anterodistal and posterodistal positions. Translations at both positions were significantly reduced, by adding the support plate, during both extension and 45-degree flexion in the fracture group. The rotation at the posterodistal position upon extension and the anterodistal position upon 45-degree flexion was significantly reduced by the support plate. The surface strain of the medial plate in the fracture group was significantly reduced by the support plate upon both extension and 45-degree flexion. INTERPRETATION: Lateral hinge fractures caused abnormal hinge movements, which were significantly reduced by the short support plate. A short support plate could be used if a hinge fracture occurs during distal femoral osteotomy, to improve lateral hinge stability.

[Mechanisms Underlying Novel Complications Associated with Neuroendovascular Therapy for Cerebrovascular Diseases].

Endovascular treatment is increasingly being accepted in clinical practice as a popular treatment modality for cerebrovascular diseases. In addition to frequently observed complications such as vessel injury, thromboembolism, and adverse effects associated with contrast media, patients may present with several unique but important complications, and clinicians should be mindful of these. In this chapter, we discuss such complications and the relevant contributory mechanisms.