Morphologic differences between ruptured and unruptured choroidal anastomosis in adult moyamoya disease: a high-resolution vessel wall imaging study.

OBJECTIVE: Choroidal anastomosis (ChA) has been implicated as the main indicator of an increased hemorrhagic risk in adult moyamoya disease. In this retrospective study, the authors aimed to identify the potential risk factors that can influence the rupture of ChA. METHODS: The authors evaluated the clinical and radiological data on brain hemispheres positive for ChA from September 2019 to March 2023. The rupture status of the ChA was determined using previously described methods. Two independent raters quantitatively investigated the lumen diameter (LD) and lumen area (LA) of the ChA using high-resolution vessel wall imaging (VWI). Multivariate logistic regression analysis was conducted to identify the risk factors for ruptured ChA. RESULTS: Ruptured and unruptured ChAs were identified in 16 and 60 hemispheres, respectively. Univariate analysis showed that the mean values of the LD (1.251 ± 0.241 vs 0.967 ± 0.214 mm, p < 0.001) and LA (1.607 ± 0.445 vs 0.945 ± 0.372 mm2, p < 0.001) of ChAs were significantly greater in the ruptured group than in the unruptured group. A periventricular anastomosis (PA) score of 1, indicating the angiographic presence of ChA alone, was more prevalent in the ruptured group than in the unruptured group (43.8% vs 11.7%, p = 0.003). Multivariate analysis demonstrated that a larger LA of the ChA (OR 37.01, 95% CI 5.787-236.7, p < 0.001) and PA score 1 (OR 6.661, 95% CI 1.260-35.21, p = 0.026) were independently associated with ruptured ChA hemispheres. Receiver operating characteristic curve analysis revealed that the optimal cutoff point for the LA was 1.285 mm2 (sensitivity 81.3%, specificity 86.7%). CONCLUSIONS: A larger LA (> 1.285 mm2) of the ChA and the angiographic presence of ChA alone are independent risk factors for a ruptured ChA. Revascularization surgery for the prevention of future hemorrhage may be indicated for hemispheres with a high-risk unruptured ChA. These characteristics may help to determine treatment strategies for patients with an unruptured ChA.

Massive Hyperostotic Meningioma En Plaque Mimicking Fibrous Dysplasia.

The authors report an extremely rare case of a massive hyperostotic meningioma en plaque, which had characteristics of unique bony growth. A 34-year-old man presented with a palpable solid mass in the left cranial region that had gradually grown in size with a broad base on the calvarium for 8 years. Radiologically, the area involved by the mass ranged from the sphenoid bone to the frontal, parietal, temporal, and occipital bones. Three-dimensional CT revealed multiple growing spiculate features on the inner and outer cranial surface. Even though the radiologic features resembled fibrous dysplasia, it was histologically found to be a type of meningioma.

High resolution vessel-wall imaging for peripheral aneurysms in adult moyamoya disease: a report of three cases.

Peripheral aneurysms in patients with moyamoya disease have been reported to be hazardous owing to their rupture-prone nature. High-resolution vessel wall imaging has recently emerged as a useful modality for evaluating intracranial aneurysmal status. We present the vessel-wall imaging of peripheral aneurysms in three patients with moyamoya disease. Strong circumferential wall enhancement was observed in ruptured peripheral aneurysms. Peripheral aneurysms were located at the connection point between the single main stem and the multiple medullary tributaries of the choroidal anastomosis. Using high-resolution vessel-wall imaging, we identified the characteristics of peripheral aneurysms in patients with moyamoya disease.

Surgical Thrombectomy for Extensive Cerebral Venous Sinus Thrombosis after COVID-19 Vaccination : A Novel Surgical Technique and Literature Review.

Surgical treatment of refractory and extensive cerebral venous sinus thrombosis (CVST) has limited applications. Here, we describe an open, direct sinus thrombectomy in the early phase of extensive CVST. A 49-year-old man with extensive CVST that occurred after the coronavirus disease 2019 (COVID-19) vaccination and affected the drainage of the Labbé vein presented with clinical deterioration and left temporal hemorrhagic infarction. Since the patient had extensive CVST, we determined that systemic anticoagulation and endovascular treatment were not suitable treatment options. Therefore, we decided on an emergency surgical treatment and performed direct surgical thrombectomy. We followed extended suboccipital approach and made multiple incisions on the sinuses, exposing the posterior superior sagittal sinus to the transverse sigmoid junction. Consequently, the clinical condition of the patient dramatically improved, resulting in a favorable outcome with a modified Rankin Scale score of 0. Performing emergency open surgical thrombectomy was a technically feasible treatment option that recanalized obstructed sinuses. Importantly, the patient recovered with a good clinical outcome. Early maximal surgical thrombectomy is an effective and lifesaving method to treat extensive CVST with hemorrhagic infarction.

Clinical significance of "periventricular collateral enhancement sign" in symptomatic moyamoya disease: A vessel wall imaging study.

BACKGROUND: Periventricular collaterals are associated with high risk of hemorrhagic stroke in adult moyamoya disease (MMD). However, the clinical significance of the periventricular collateral enhancement sign (PCES), which indicates wall enhancement of periventricular collaterals on contrast-enhanced vessel wall imaging (VWI), has yet to be determined. METHODS: Thirty-seven patients with MMD with acute neurological symptoms were consecutively recruited. Periventricular collaterals including lenticulostriatal artery, thalamic artery, and choroidal artery collaterals were evaluated on digital subtraction angiography, and then PCES was detected on pre- and postcontrast VWI. First, the association between PCES and hemorrhagic presentation was evaluated using multivariate analyses. Second, two raters investigated the culprit vessels responsible for bleeding in hemorrhagic MMD using the Cohen kappa statistic. RESULTS: Fifteen sites of PCES on postcontrast VWI were observed in 15 patients. Multivariate analysis revealed that hemorrhagic presentation was the only independent factor for PCES (OR = 37.3, 95%CI = 3.9-113, p =.002). In patients with hemorrhagic presentation (n = 20), the identification rate of the ruptured vessel was 80% by rater 1, with excellent agreement. (inter-rater, κ = 0.86, 95%CI = 0.59-1.00; intra-rater, κ = 0.83, 95%CI = 0.50-1.00). Choroidal (50%) and thalamic artery collaterals (15%) were the most common and the second most common types of culprit vessels. Inter-rater and intra-rater reliabilities for the classification of culprit vessels were also excellent (intra-rater, κ = 0.86, 95%CI = 0.67-1.00; inter-rater, κ = 0.93, 95%CI = 0.79-1). CONCLUSION: Acute hemorrhagic stroke in MMD is independently associated with PCES on postcontrast VWI. PCES can help to detect the culprit vessels that are responsible for hemorrhage in patients with MMD.

Diagnostic Performance of High-Resolution Vessel Wall Magnetic Resonance Imaging and Digital Subtraction Angiography in Intracranial Vertebral Artery Dissection.

PURPOSE: Intracranial vertebral artery dissection (VAD) is being increasingly recognized as a leading cause of Wallenberg syndrome and subarachnoid hemorrhage. Conventional angiography is considered the standard diagnostic modality, but the diagnosis of VAD remains challenging. This study aimed to compare the diagnostic performance of high-resolution vessel wall imaging (HR-VWI) with digital subtraction angiography (DSA) for intracranial VAD. MATERIALS AND METHODS: Twenty-four patients with 27 VADs, who underwent both HR-VWI and DSA within 2 weeks, were consecutively enrolled in the study from March 2016 to September 2020. HR-VWI and DSA were performed to diagnose VAD and to categorize its angiographic features as either definite dissection or suspicious dissection. Features of HR-VWI were used to evaluate direct arterial wall imaging. The reference standard was set from the clinicoradiologic diagnosis. Two independent raters evaluated the angiographic features, dissection signs, and interrater agreement. Each subject was also dichotomized into two groups (suspicious or definite VAD) in each modality, and diagnosis from HR-VWI and DSA was compared with the final diagnosis by consensus. RESULTS: HR-VWI had higher agreement (90.6% vs. 53.1%) with the final diagnosis and better interrater reliability (kappa value (κ) = 0.91; 95% confidence interval (CI) = 0.64-1.00) compared with DSA (κ = 0.58; 95% CI = 0.35-1.00). HR-VWI provided a more detailed identification of dissection signs (77.7% vs. 22.2%) and better reliability (κ = 0.88; 95% CI = 0.58-1.00 vs. κ = 0.75; 95% CI = 0.36-1.00), compared to DSA. HR-VWI was comparable to DSA for the depiction of angiographic features for VAD. CONCLUSIONS: HR-VWI may be useful to evaluate VAD, with better diagnostic confidence compared to DSA.

Geometric Classification of Paraclinoid Aneurysms for Microcatheter Superselection in Coil Embolization.

AIM: To suggest a geometric classification of paraclinoid aneurysms for microcatheter superselection. MATERIAL AND METHODS: Clinical data from 76 patients (80 paraclinoid aneurysms) who underwent endovascular treatments were retrospectively reviewed. Paraclinoid aneurysms were classified according to the six directions where the aneurysm neck lies and simplified into three groups as follows: superior, medial, and lateral groups. The medial group was further divided into proximal, mid, and distal subgroups according to the location of the aneurysm neck on lateral angiography. Furthermore, we assessed the superselection success rate with the first-selected pre-shaped microcatheter per group. RESULTS: According to the aneurysm direction, the medial group showed relatively lower superselection success rates (66.1%) than the superior (81.8%) and lateral groups (85.7%). The S-shaped microcatheter was the most frequently used in the superior (69.2%) and lateral groups (62.5%). Acute-angled J- and C-shaped microcatheters (88.5%) were preferred for proximal aneurysms; and obtuse-angled 45°- and 90°-angled microcatheters (75%), for distal aneurysms. The mid-portion group showed the lowest success rate (45.8%) and more difficulties in pre-shaped microcatheter superselection. CONCLUSION: Medially directed mid-portion aneurysms were difficult to access using pre-shaped microcatheters; thus, tailored steam-shaping techniques may be considered. Superiorly and laterally directed aneurysms could be accessed using pre-S-shaped microcatheters. Acute-angled microcatheters may be considered for proximal aneurysms; and obtuse-angled microcatheters, for distal aneurysms.

Incidental Microaneurysms During Microvascular Surgery: Incidence, Treatment, and Significance.

BACKGROUND: Although new imaging tools have been developed for the detection of smaller aneurysms, angiographically negative microaneurysms are still encountered during cerebral microsurgery. Currently, only limited information regarding incidence and efficacy of treatment of these microaneurysms is available. METHODS: We investigated the incidence and treatment of incidental microaneurysms (IMAs) in the last 5 years. IMAs are unidentifiable and invisible on preoperative angiography, but are detected during microvascular surgery. The inclusion criteria were aneurysm cases treated with microsurgery via transsylvian approaches, and those undergoing preoperative digital subtraction angiography. RESULTS: This study enrolled 484 surgical cases (248 cases of subarachnoid hemorrhage and 236 cases of unruptured aneurysms) in 460 patients, and 33 tiny aneurysms were found in 31 operative cases (6.4% incidence per operation). The most typical type was located on another branching site of the middle cerebral artery found during neck clipping of the middle cerebral artery bifurcation aneurysm. A patient with multiple aneurysms presented a statistically significant risk (375/78 vs. 15/16; P < 0.001) of IMA identification. IMAs were treated by clipping and wrapping in 18 and 15 cases, respectively, without complications. CONCLUSIONS: This study revealed a 6.4% incidence of IMAs; however, this could be underestimated because of the limited range of inspection. Early detection of an IMA through careful inspection during microvascular surgery could be beneficial, especially in patients with multiple aneurysms.

Life-Threatening Hemothorax Caused by Spontaneous Extracranial Vertebral Aneurysm Rupture in Neurofibromatosis Type 1.

BACKGROUND: Although vascular abnormality is an uncommon comorbidity of neurofibromatosis type 1 (NF1), it is potentially fatal. We present spontaneous hemothorax caused by rupture of a vertebral artery (VA) aneurysm in a patient with NF1. CASE DESCRIPTION: A 36-year-old man with a history of NF1 was transferred to the emergency department with dyspnea. Chest computed tomography scan revealed hemothorax in the left lung field with mediastinal shifting and aneurysmal dilatation of the left VA at the C6 vertebra level. Immediate drainage of the hematoma by chest tube insertion was performed. Diagnostic angiogram showed a 3- to 4-cm fusiform aneurysm of the VA. After the angiogram, cardiopulmonary arrest occurred after a rebleed of the VA aneurysm. The aneurysmal segment of the VA was urgently occluded with detachable coils. Postoperatively, the patient was in intensive care for 1 month because of fulminant pneumonia. After the patient regained consciousness, he was found to have right hemiparesis from a small infarction at the pons. The patient's function improved to near normal after 1 year of recovery. CONCLUSIONS: Hemothorax caused by VA rupture in a patient with NF1 is an extremely rare condition that can be fatal. Careful examination with suspicion for early detection and treatment is required for this urgent condition. Endovascular coiling was safe even for an unstable patient with massive bleeding.

Intracranial Arterial Tortuosity According to the Characteristics of Intracranial Aneurysms.

OBJECTIVE: Intracranial aneurysm (IA) is the leading cause of subarachnoid hemorrhage. The pathomechanisms of IA are poorly understood but can be related to arterial tortuosity resulting from underlying systemic factors leading to arterial wall weakening. We aimed to analyze the tortuosity of the intracranial artery in a cohort with IA, hypothesizing that the tortuosity of intracranial arteries differs depending on the characteristics of the IA. METHODS: Patients with saccular IA were consecutively enrolled. Clinical factors and vascular tortuosity of the right and left middle cerebral arteries and basilar artery (BA) of all patients with IA were compared according to the characteristics of the IA: 1) ruptured versus unruptured, 2) multiple versus single, and 3) large (>5 cm) versus small (≤5 cm). Unruptured IAs were comparatively analyzed according to aneurysm size and aspect ratio, whereas ruptured IAs were analyzed according to aneurysm size. RESULTS: Two hundred eighty-five patients were enrolled (mean age, 59 years; 71.2% women). The tortuosity of the BA was higher in the large IA group (5.63 ± 6.26; n = 133; P = 0.009), large unruptured IA group (6.64 ± 6.32; n = 53; P = 0.039), and large ruptured IA group (5.50 ± 6.52; n = 80; P = 0.033) compared with the small IA, small unruptured IA, and small ruptured IA group. In multivariate analysis, increased BA tortuosity was significantly associated with large IAs (ß = 1.066; P = 0.008), unruptured large IAs (ß = 1.077; P = 0.033), and ruptured large IAs (ß = 1.086; P = 0.025). CONCLUSIONS: The BA tortuosity was higher in patients with large IAs, which may represent an imaging biomarker of aneurysm growth.

Gamma knife radiosurgery for trigeminal schwannoma: a 20-year experience with long-term treatment outcome.

PURPOSE: This study evaluated the long-term tumor control rate (TCR) and symptomatic outcomes of patients treated with gamma knife radiosurgery (GKRS) for trigeminal schwannomas (TSs). METHODS: Thirty-two patients with TS who underwent GKRS between January 1994 and January 2013 with at least 2 years of follow-up were enrolled in the study. Clinical charts and surgical records were retrospectively reviewed to evaluate factors affecting TCR and symptomatic outcomes. The median patient age was 57.5 years (max = 81, interquartile range [IQR] = 51-67), and the median tumor volume was 3.55 cm3 (max = 25.2 cm3, IQR = 2.0-6.2 cm3). The median marginal and maximum doses were 13.0 Gy (max = 18.0 Gy, IQR = 12.5-15 Gy) and 23.8 Gy (max = 35 Gy, IQR = 21.7-25.0 Gy), respectively. RESULTS: At a median follow-up of 90.5 months (max = 281 months, IQR = 49-139.75 months), the actuarial 3-, 5-, and 10-year TCR were 93.8, 86.2, and 80.8%, respectively. Our data and multivariate analysis indicated that the target volume was the only significant factor determining TCR and that larger tumors (> 5 cm3) were more likely to progress (p = 0.011). Cystic tumors had a higher incidence of transient enlargement and temporary symptom change compared to those in solid tumors. An unfavorable outcome of symptoms was observed in five patients (15.6%). Complications were observed in two patients (6.25%), including hydrocephalus and radio-induced trigeminal neuropathy, respectively. CONCLUSIONS: GKRS can be a safe and effective treatment modality for TS with long-term follow-up, especially for small tumors. An extended period of follow-up observation is required to conclude the clinical response to GKRS.

A label-free cellulose SERS biosensor chip with improvement of nanoparticle-enhanced LSPR effects for early diagnosis of subarachnoid hemorrhage-induced complications.

It is very difficult to predict some complications after subarachnoid hemorrhage (SAH), despite rapid advances in medical science. Herein, we introduce a label-free cellulose surface-enhanced Raman spectroscopy (SERS) biosensor chip with pH-functionalized, gold nanoparticle (AuNP)-enhanced localized surface plasmon resonance (LSPR) effects for identification of SAH-induced cerebral vasospasm and hydrocephalus caused by cerebrospinal fluid (CSF). The SERS biosensor chip was implemented by the synthesis reaction of the AuNPs, which were charged positively through pH level adjustment, onto a negatively-charged cellulose substrate with ξ = -30.7 mV. The zeta potential, nanostructural properties, nanocrystallinity, and computational calculation-based electric field distributions of the cellulose-originated AuNPs were optimized to maximize LSPR phenomena and then characterized. Additionally, the performance of the SERS biosensor was compared under two representative excitation laser sources in the visible region (532 nm) and near-infrared region (785 nm). The Raman activities of our SERS biosensor chip were evaluated by trace small molecules (crystal violet, 2 µL), and the biosensor achieved an enhancement factor of 3.29 × 109 for the analytic concept with an excellent reproducibility of 8.5% relative standard deviation and a detection limit of 0.74 pM. Furthermore, the experimental results revealed that the five proposed SERS-based biomarkers could provide important information for identifying and predicting SAH-induced cerebral vasospasm and hydrocephalus complications (91.1% reliability and 19.3% reproducibility). Therefore, this facile and effective principle of our SERS biosensor chip may inspire the basis and strategies for the development of sensing platforms to predict critical complications in various neurosurgical diagnoses.

In Situ Side-to-Side Anastomosis: Surgical Technique and Complication Avoidance.

In situ side-to-side (STS) anastomosis is a unique technique used for intracranial artery-intracranial artery revascularization. Over a 7-year period, 7 STS anastomoses were performed for anterior cerebral artery aneurysms in 6 patients and a posteroinferior cerebellar artery aneurysm in 1 patient. We provide a step-by-step guide for suturing techniques from arteriotomy to vessel wall sutures based on clinical experiences, with detailed illustrations. Technical considerations in each stage are also discussed. The current technique provides a viable option for treatment of complex aneurysms.

Surgical Revascularization for the Treatment of Complex Anterior Cerebral Artery Aneurysms: Experience and Illustrative Review.

BACKGROUND: Many methods for treating complex anterior cerebral artery (ACA) aneurysms are available; however, there is substantial variation among methods because of various aneurysm locations, the relationship of the aneurysm to arterial branches, aneurysm size and other morphologic characteristics, and the diameters of the parent or branching arteries. METHODS: We reviewed complex ACA aneurysms based on both our own experience and the available literature. Each unique case is analyzed in terms of the characteristics of the aneurysm, along with analysis and classification of the revascularization method used. Computer tablet-drawn illustrations of each unique technique are provided for comprehension and application in various situations. RESULTS: Over 6 years, we treated 5 cases of complex ACA aneurysms (1 precommunicating, 1 communicating, 1 postcommunicating, and 2 precallosal-supracallosal segment) with revascularization. Side-to-side anastomoses included pericallosal ACA segment-pericallosal ACA segment in 3 cases, supracallosal ACA segment-supracallosal ACA segment in 1 case, and ipsilateral callosomarginal artery-pericallosal artery in 1 case. Final modified Rankin scale score was 0 in 4 of 5 cases and 3 in 1 case. Six treatment strategies were used for the precommunicating aneurysm, 8 for the communicating aneurysm, 7 for the postcommunicating aneurysm, and 9 for the 2 precallosal-supracallosal segment aneurysms. CONCLUSIONS: Treatment of complex ACA aneurysms should be tailored according to the location and nature of the aneurysm and collateral circulation. Viable and feasible treatment strategies must be established by the neurovascular surgeon.

Clinical outcomes and radiosurgical considerations for pediatric arteriovenous malformation: influence of clinical features on obliteration rate.

PURPOSE: Gamma knife radiosurgery (GKRS) is an established treatment modality for brain arteriovenous malformation (AVM), but there have been few published studies examining the relationship between clinical features of AVM and successful obliteration with GKRS in pediatric patients. In the current study, we investigate the outcomes of GKRS for pediatric patients with brain AVM and analyze the variables that influence obliteration. METHODS: We analyzed 68 pediatric patients (≤ 18 years) with a mean follow-up period of 61.9 months (range 6-215 months). The following parameters were analyzed to determine their influence on obliteration of AVM treated by GKRS: age, sex, target volume, irradiation dose, prior treatment, location of AVM, nidus structure, velocity of AVM, location of venous drainage, number of feeding arteries, and initial presenting symptoms. Also, we estimated clinical factors which should be considered during the follow-up period. RESULTS: Of the 68 patients, complete obliteration was confirmed in 26 (38.2%) by cerebral angiography. The response rate of AVM for GKRS was 92.6%. No significant association was observed between any of the parameters investigated and the obliteration of AVM, with the exception of number of feeding arteries, which exhibited a statistically significant difference by univariate analysis (p = 0.003). However, on multivariate analysis, nidus structure (p = 0.007), velocity of the main arterial phase (p = 0.013), velocity of the feeding artery phase (p = 0.004), and the number of feeding arteries (p = 0.018) showed statistical significance. CONCLUSION: GKRS yielded good long-term clinical outcomes in most pediatric patients. Multiple arterial feeding vessels, diffuse nidus structure, and fast flow of AVM were specific factors associated with a low rate of obliteration in pediatric AVMs.

Affordable self-regulating irrigation device for microsurgery using readily available malleable wire and a Silastic tube: a technical note.

BACKGROUND: A relevant irrigating and flushing maneuver during cerebral microsurgical procedures allows for a neat and optimal operative field. However, when operating on the deep region of the brain, a delicately created slim surgical corridor could unintentionally hinder the assisting surgeon from properly performing this routine maneuver. METHOD: To address this problem, the authors devised a useful and convenient irrigation system that can be used during cerebral microsurgery. RESULTS: This system only necessitates a readily available silastic feeding tube and a malleable wire. The advantages of our devised system include the convenience of free molding, good endurance of the molded contour, and easy control over the amount of irrigation. CONCLUSIONS: In this report, the authors demonstrated technical tips for using this newly devised system.

A Portable Training Model for Deep Bypass Surgery.

INTRODUCTION: Deep bypass surgery remains a challenging operative procedure. For novice trainees, there is a high barrier to improving the microsurgical skills needed for this procedure because of the relatively low number of cases and the high cost of microsurgical instruments. Here, the authors introduce a training model that includes highly accessible devices and does not require a microscope. MATERIALS AND METHODS: The surgical environment consisted of two 15.5-cm straight serrated forceps with a 1-mm tip width (Medicon, Tuttlingen, Germany), 9-cm curved iris scissors (Medicon), 4-0 black silk suture, gauze, and a 15 × 10.5 × 3.5-cm-sized box with a transparent cover. These materials are affordable even in low-income countries. PROCEDURE: To understand and learn the hand positioning used in the deep surgical field, suturing practice was performed as follows: the forceps and a needle were placed in a slanted position, with hand position maintained at a 50° angle between the 2 forceps. This was also performed above the desk, without wrist support. CONCLUSIONS: Our training system will be helpful, especially for deep bypass surgery, since training with similar muscle effort and fatigue can improve surgical skills. This system is economic, highly accessible, and available even for portable training.

Rescue bypass for the treatment of pseudoaneurysm on the distal anterior cerebral artery: a case report of vertical side-to-side anastomosis of the distal callosomarginal artery-pericallosal artery.

Pseudoaneurysm on the distal anterior cerebral artery (ACA) is rare but potentially fatal. It usually cannot be treated with typical treatment modalities. A 47-year-old female patient was diagnosed with a ruptured aneurysm on the pericallosal artery (PerA). During surgical exploration, it was found to be a pseudoaneurysm and could not be treated with clipping. We performed surgical trapping of the involved segment of the proximal PerA followed by side-to-side anastomosis between the ipsilateral PerA and the callosomarginal artery. The patient recovered without any neurologic deficit. This new method of anastomosis could be an alternative option.

Puncture of Cerebellar Horizontal Fissure for Retrosigmoid Approach: A Prospective and Quantitative Analysis.

BACKGROUND: Cerebrospinal fluid (CSF) drainage is important in retrosigmoid approached surgery; however, in some cases, it is not feasible due to cerebellar swelling. OBJECTIVE: To introduce a method, puncture of the horizontal fissure of the cerebellum, which can reduce the cerebellum to easily obtain a good operative corridor and slowly drain CSF. METHODS: Between January and December 2014, we estimated the precise location of the horizontal fissure in 56 patients who underwent surgery via a retrosigmoid approach. Then, we collected and analyzed CSF drained by puncturing the horizontal fissure. We investigated whether a good operative corridor was obtained with this method. RESULTS: The location of the precise horizontal fissure was a mean of 3.97 mm caudal to transverse sinus and the mean amount of CSF drained in 56 patients was 50.4 mL. A good corridor was obtained in 46 (82.1%) of 56 patients without additional cistern puncture. CONCLUSION: The puncture of the horizontal fissure can be useful in retrosigmoid approach surgery. Moreover, inexperienced surgeons can use this method to effectively avoid injury of the cerebellum.

An Affordable Microsurgical Training System for a Beginning Neurosurgeon: How to Realize the Self-Training Laboratory.

OBJECTIVE: To provide detailed information about how to realize a self-training laboratory with cost-effective microsurgical instruments, especially pertinent for the novice trainee. METHODS: Our training model is designed to allow the practice of the microsurgery skills in an efficient and cost-effective manner. A used stereoscopic microscope is prepared for microsurgical training. A sufficient working distance for microsurgical practice is obtained by attaching an auxiliary objective lens. The minimum instrument list includes 2 jeweler's forceps, iris scissors, and alligator clips. The iris scissors and alligator clip provide good alternatives to micro-scissors and microvascular clamp. RESULTS: The short time needed to set up the microscope and suture the gauze with micro-forceps makes the training model suitable for daily practice. It takes about 15 minutes to suture 10 neighboring fibers of the gauze with 10-0 nylon; thus, training can be completed more quickly. CONCLUSIONS: We have developed an inexpensive and efficient micro-anastomosis training system using a stereoscopic microscope and minimal micro-instruments. Especially useful for novice trainees, this system provides high accessibility for microsurgical training.