Effect of different positive end expiratory pressure levels on optic nerve sheath diameter in patients with or without midline shift who are undergoing supratentorial craniotomy.

PURPOSE: In general, high levels of PEEP application is avoided in patients undergoing craniotomy to prevent a rise in ICP. But that approach would increase the risk of secondary brain injury especially in hypoxemic patients. Because the optic nerve sheath is distensible, a rise in ICP is associated with an increase in the optic nerve sheath diameter (ONSD). The cutoff value for elevated ICP assessed by ONSD is between 5.6 and 6.3 mm. We aimed to evaluate the effect of different PEEP levels on ONSD and compare the effect of different PEEP levels in patients with and without intracranial midline shift. METHODS: This prospective observational study was performed in aged 18-70 years, ASA I-III, 80 patients who were undergoing supratentorial craniotomy. After the induction of general anesthesia, the ONSD's were measured by the linear transducer from 3 mm below the globe at PEEP values of 0-5-10 cmH2O. The ONSD were compered between patients with (n = 7) and without midline shift (n = 73) at different PEEP values. RESULTS: The increases in ONSD due to increase in PEEP level were determined (p < 0.001). No difference was found in the comparison of ONSD between patients with and without midline shift in different PEEP values (p = 0.329, 0.535, 0.410 respectively). But application of 10 cmH2O PEEP in patients with a midline shift increased the mean ONSD value to 5.73 mm. This value is roughly 0.1 mm higher than the lower limit of the ONSD cutoff value. CONCLUSIONS: The ONSD in adults undergoing supratentorial tumor craniotomy, PEEP values up to 5 cmH2O, appears not to be associated with an ICP increase; however, the ONSD exceeded the cutoff for increased ICP when a PEEP of 10 cmH2O was applied in patients with midline shift.

Long-term results of minimally invasive strip craniectomy without helmet therapy for scaphocephaly - a single-centre experience.

Scaphocephaly is the most common type of craniosynostosis and various surgical techniques are used for treatment. Due to late postoperative changes of the head shape, long-term outcome data is important for evaluating any new surgical technique. At our institution, minimally invasive strip craniectomy without regular helmet therapy is the standard treatment in scaphocephalic patients. Between October 2021 and February 2023, we retrospectively examined the skull shape of patients who underwent minimally invasive strip craniectomy for scaphocephaly using a 3D surface scan technique. The cephalic index (CI), the need for helmet therapy and additional cosmetic outcome parameters were investigated. We included 70 patients (72.5% male). The mean follow-up time was 46 (10-125) months and the mean CI was 75.7 (66.7-85.2). In 58 patients, the final cosmetic result was rated as "excellent/good" (mean CI: 76.3; 70.4-85.0), in 11 as "intermediate" (mean CI: 73.3; 66.7-77.6), and in one case as "unsatisfactory" (CI 69.3). The presence of a suboccipital protrusion was associated with a "less than good" outcome. The CI correlated significantly with the overall outcome, the presence of frontal bossing, and the interval between scan and surgery (age at scan). Minimally invasive strip craniectomy is an elegant and safe method to correct scaphocephaly. Our data show good cosmetic results in the long term even without regular postoperative helmet therapy.

Clinical outcomes and complications of eyelid versus eyebrow approaches to supraorbital craniotomy: systematic review and indirect meta-analysis.

OBJECTIVE: Eyebrow supraorbital craniotomy is a versatile keyhole technique for treating intracranial pathologies. The eyelid supraorbital approach, an alternative approach to an eyebrow supraorbital craniotomy, has not been widely adopted among most neurosurgeons. The purpose of this systematic review and meta-analysis was to perform a pooled analysis of the complications of eyebrow or eyelid approaches for the treatment of aneurysms, meningiomas, and orbital tumors. METHODS: A systematic review of the literature in the PubMed, Embase, and Cochrane Review databases was conducted for identifying relevant literature using keywords such as "supraorbital," "eyelid," "eyebrow," "tumor," and "aneurysm." Eyebrow supraorbital craniotomies with or without orbitotomies and eyelid supraorbital craniotomies with orbitotomies for the treatment of orbital tumors, intracranial meningiomas, and aneurysms were selected. The primary outcomes were overall complications, cosmetic complications, and residual aneurysms and tumors. Secondary outcomes included five complication domains: orbital, wound-related, scalp or facial, neurological, and other complications. RESULTS: One hundred three articles were included in the synthesis. The pooled numbers of patients in the eyebrow and eyelid groups were 4689 and 358, respectively. No differences were found in overall complications or cosmetic complications between the eyebrow and eyelid groups. The proportion of residuals in the eyelid group (11.21%, effect size [ES] 0.26, 95% CI 0.12-0.41) was significantly higher (p < 0.05) than that in the eyebrow group (6.17%, ES 0.10, 95% CI 0.08-0.13). A subgroup analysis demonstrated significantly higher incidences of orbital, wound-related, and scalp or facial complications in the eyelid group (p < 0.05), but higher other complications in the eyebrow group. Performing an orbitotomy substantially increased the complication risk. CONCLUSIONS: This is the first meta-analysis that quantitatively compared complications of eyebrow versus eyelid approaches to supraorbital craniotomy. This study found similar overall complication rates but higher rates of selected complication domains in the eyelid group. The literature is limited by a high degree of variability in the reported outcomes.

Anterolateral keyhole transorbital routes to the skull base: a comparative anatomical study.

OBJECTIVE: Although keyhole transorbital approaches are gaining traction, their indications have not been adequately studied comparatively. In this study the authors have defined them also as transwing approaches-meaning that they use the different facies of the sphenoid wing for cranial entry-and sought to compare the four major ones: 1) lateral orbitocraniotomy through a lateral canthal incision (LatOrb); 2) modified orbitozygomatic approach through a palpebral incision (ModOzPalp); 3) modified orbitozygomatic approach through an eyebrow incision (ModOzEyB); and 4) supraorbital craniotomy through an eyebrow incision (SupraOrb), coupled with its expanded version (SupraTransOrb). METHODS: Cadaveric dissections were performed at the neuroanatomy lab. To delineate the skull base exposure, four formalin-fixed heads were used, with two sides dedicated to each approach. The outer limits were assessed via image guidance and were mapped and illustrated accordingly. A fifth head was dissected purely endoscopically, just to facilitate an overview of the transwing concept. Qualitative features were also rigorously examined. RESULTS: The LatOrb proves to be more versatile in the middle cranial fossa (MCF), whereas the anterior cranial fossa (ACF) exposure is limited to a small area above the sphenoid ridge. An anterior clinoidectomy is possible; however, the exposure of the roof of the optic canal is suboptimal. The ModOzPalp adequately exposes both the ACF and MCF. Its lateral trajectory allows the inferior to superior view, yet there is restricted access to the medial anterior skull base (olfactory groove). The ModOzEyB also provides extensive exposure of the ACF and MCF, but has a more superior to inferior trajectory compared to the ModOzPalp, making it more appropriate for pathology reaching the medial anterior skull base or even the contralateral side. The anterior clinoidectomy is performed with improved visualization of the optic canal. The SupraOrb provides mainly anterior cranial base exposure, with minimal middle fossa. An anterior clinoidectomy can be performed, but without any direct observation of the superior orbital fissure. Some MCF access can be accomplished if the lateral sphenoid wing is drilled inferiorly, leading to its highly versatile variant, the SupraTransOrb. CONCLUSIONS: All the aforementioned approaches use the sphenoid wing as skull base corridor from a specific orientation point; hence these are designated as transwing approaches. Their peculiarities mandate careful case selection for the effective and safe completion of the surgical goals.

360° around the orbit: key surgical anatomy of the microsurgical and endoscopic cranio-orbital and orbitocranial approaches.

OBJECTIVE: Several pathologies either invade or arise within the orbit. These include meningiomas, schwannomas, and cavernous hemangiomas among others. Although several studies describing various approaches to the orbit are available, no study describes all cranio-orbital and orbitocranial approaches with clear, surgically oriented anatomical descriptions. As such, this study aimed to provide a comprehensive guide to the microsurgical and endoscopic approaches to and through the orbit. METHODS: Six formalin-fixed, latex-injected cadaveric head specimens were dissected in the surgical anatomy laboratory at the authors' institution. In each specimen, the following approaches were modularly performed: endoscopic transorbital approaches (ETOAs), including a lateral transorbital approach and a superior eyelid crease approach; endoscopic endonasal approaches (EEAs), including those to the medial orbit and optic canal; and transcranial approaches, including a supraorbital approach, a fronto-orbital approach, and a 3-piece orbito-zygomatic approach. Each pertinent step was 3D photograph-documented with macroscopic and endoscopic techniques as previously described. RESULTS: Endoscopic endonasal approaches to the orbit afforded excellent access to the medial orbit and medial optic canal. Regarding ETOAs, the lateral transorbital approach afforded excellent access to the floor of the middle fossa and, once the lateral orbital rim was removed, the cavernous sinus could be dissected and the petrous apex drilled. The superior eyelid approach provides excellent access to the anterior cranial fossa just superior to the orbit, as well as the dura of the lesser wing of the sphenoid. Craniotomy-based approaches provided excellent access to the anterior and middle cranial fossa and the cavernous sinus, except the supraorbital approach had limited access to the middle fossa. CONCLUSIONS: This study outlines the essential surgical steps for major cranio-orbital and orbitocranial approaches. Endoscopic endonasal approaches offer direct medial access, potentially providing bilateral exposure to optic canals. ETOAs serve as both orbital access and as a corridor to surrounding regions. Cranio-orbital approaches follow a lateral-to-medial, superior-to-inferior trajectory, progressively allowing removal of protective bony structures for proportional orbit access.

A Review of the Current Management of Intracranial Infections of Neurosurgical Importance.

Surgically treated intracranial infections are among the common disease entities seen in neurosurgical practice. Several microbiological agents such as bacteria and fungi have been identified as responsible for intracranial infection. It affects all age groups, though microbial agents and risk factors vary with age. Presentation is non-specific and it requires a high index of suspicion, especially with a background febrile illness such as in the setting of poorly-treated meningitis and immunosuppressive conditions such as retroviral illness. Contrast-enhanced magnetic resonance imaging (MRI) scan is the diagnostic tool of choice; it helps to confirm the diagnosis and exclude other ring-enhancing lesions such as glioblastoma and metastatic brain tumours. Treatment involves medical and/or surgical treatment with clear indications. Surgical treatment includes the drainage of abscess via a twist drill or burrhole craniostomy, and craniotomy for recurrent cases. The advances recorded in the evolution of antibiotics and neuroimaging have helped to improve the outcomes of these patients with intracranial infection.

Les infections intracrâniennes traitées chirurgicalement font partie des entités pathologiques courantes rencontrées en pratique neurochirurgicale. Plusieurs agents microbiologiques tels que les bactéries et les champignons ont été identifiés comme responsables des infections intracrâniennes. Cela affecte tous les groupes d'âge, bien que les agents microbiens et les facteurs de risque varient avec l'âge. La présentation est non spécifique et nécessite un haut degré de suspicion, surtout en présence d'une maladie fébrile sous-jacente, comme dans le cas d'une méningite mal traitée et de conditions immunosuppressives telles que l'infection rétrovirale. L'imagerie par résonance magnétique (IRM) avec contraste est l'outil diagnostique de choix ; elle aide à confirmer le diagnostic et à exclure d'autres lésions à rehaussement annulaire telles que le glioblastome et les tumeurs cérébrales métastatiques. Le traitement implique un traitement médical et/ou chirurgical avec des indications claires. Le traitement chirurgical comprend le drainage de l'abcès par une trépanation ou une craniostomie à trou de trepan, et la craniotomie pour les cas récurrents. Les progrès enregistrés dans l'évolution des antibiotiques et de la neuro-imagerie ont contribué à améliorer les résultats de ces patients atteints d'infections intracrâniennes. MOTS-CLÉS: intracrânien, infection, abcès, antibiotiques, chirurgie.

Association of persistent postoperative hyperglycemia with mortality after elective craniotomy.

OBJECTIVE: The influence of persistent postoperative hyperglycemia after craniotomy has not yet been explored. This study aimed to investigate the hypothesis that persistent postoperative hyperglycemia is associated with mortality in patients undergoing an elective craniotomy. METHODS: This study included adult patients (age ≥ 18 years) undergoing an elective craniotomy between January 2011 and March 2021 at the West China Hospital, Sichuan University. Peak daily blood glucose values measured within the first 7 days after craniotomy were collected. Persistent hyperglycemia was defined by two or more consecutive serum glucose levels of mild, moderate, or severe hyperglycemia. Normoglycemia, mild hyperglycemia, moderate hyperglycemia, and severe hyperglycemia were defined as glucose values of ≤ 6.1 mmol/L, > 6.1 and ≤ 7.8 mmol/L, > 7.8 and ≤ 10.0 mmol/L, and > 10.0 mmol/L, respectively. RESULTS: This study included 14,907 patients undergoing an elective craniotomy. In the multivariable analysis, both moderate (adjusted OR 3.76, 95% CI 2.68-5.27) and severe (adjusted OR 3.82, 95% CI 2.54-5.76) persistent hyperglycemia in patients were associated with higher 30-day mortality compared with normoglycemia. However, this association was not observed in patients with mild hyperglycemia (adjusted OR 1.32, 95% CI 0.93-1.88). Interestingly, this association was observed regardless of whether patients had preoperative hyperglycemia. There was no interaction between moderate or severe hyperglycemia and preexisting diabetes (p for interaction = 0.65). When postoperative peak blood glucose values within the first 7 days after craniotomy were evaluated as a continuous variable, for each 1-mmol/L increase in blood glucose, the adjusted OR of 30-day mortality was 1.17 (95% CI 1.14-1.21). Postoperative blood glucose (area under the curve [AUC] = 0.78) was superior to preoperative blood glucose (AUC = 0.65; p < 0.001) for predicting mortality. Moderate and severe persistent hyperglycemia in patients were associated with an increased risk of deep venous thrombosis (adjusted OR 3.20, 95% CI 2.31-4.42), pneumonia (adjusted OR 2.77, 95% CI 2.40-3.21), myocardial infarction (adjusted OR 4.38, 95% CI 3.41-5.61), and prolonged hospital stays (adjusted OR 1.43, 95% CI 1.29-1.59). CONCLUSIONS: In patients undergoing an elective craniotomy, moderate and severe persistent postoperative hyperglycemia were associated with an increased risk of mortality compared with normoglycemia, regardless of preoperative hyperglycemia.

Resection of the quadrangular lobule of the cerebellum to increase exposure of the cerebellomesencephalic fissure: an anatomical study with clinical correlation.

OBJECTIVE: The lateral aspect of the cerebellomesencephalic fissure frequently harbors vascular pathology and is a common surgical corridor used to access the pons tegmentum, as well as the cerebellum and its superior and middle peduncles. The quadrangular lobule of the cerebellum (QLC) represents an obstacle to reach these structures. The authors sought to analyze and compare exposure of the cerebellar interpeduncular region (CIPR) before and after QLC resection and provide a case series to evaluate its clinical applicability. METHODS: Forty-two sides of human brainstems were prepared with Klingler's method and dissected. The exposure area before and after resection of the QLC was measured and statistically studied. A case series of 59 patients who underwent QLC resection for the treatment of CIPR lesions was presented and clinical outcomes were evaluated at 1-year follow-up. RESULTS: The anteroposterior surgical corridor of the CIPR increased by 10.3 mm after resection of the QLC. The mean exposure areas were 42 mm2 before resection of the QLC and 159.6 mm2 after resection. In this series, ataxia, extrapyramidal syndrome, and akinetic mutism were found after surgery. However, all these cases resolved within 1 year of follow-up. Modified Rankin Scale score improved by 1 grade, on average. CONCLUSIONS: QLC resection significantly increased the exposure area, mainly in the anteroposterior axis. This surgical strategy appears to be safe and may help the neurosurgeon when operating on the lateral aspect of the cerebellomesencephalic fissure.

Minimally invasive keyhole approach for supramaximal frontal glioma resections: technical note.

OBJECTIVE: The authors aimed to review the frontal lobe's surgical anatomy, describe their keyhole frontal lobectomy technique, and analyze the surgical results. METHODS: Patients with newly diagnosed frontal gliomas treated using a keyhole approach with supramaximal resection (SMR) from 2016 to 2022 were retrospectively reviewed. Surgeries were performed on patients asleep and awake. A human donor head was dissected to demonstrate the surgical anatomy. Kaplan-Meier curves were used for survival analysis. RESULTS: Of the 790 craniotomies performed during the study period, those in 47 patients met our inclusion criteria. The minimally invasive approach involved four steps: 1) debulking the frontal pole; 2) subpial dissection identifying the sphenoid ridge, olfactory nerve, and optic nerve; 3) medial dissection to expose the falx cerebri and interhemispheric structures; and 4) posterior dissection guided by motor mapping, avoiding crossing the inferior plane defined by the corpus callosum. A fifth step could be added for nondominant lesions by resecting the inferior frontal gyrus. Perioperative complications were recorded in 5 cases (10.6%). The average hospital length of stay was 3.3 days. High-grade gliomas had a median progression-free survival of 14.8 months and overall survival of 23.9 months. CONCLUSIONS: Keyhole approaches enabled successful SMR of frontal gliomas without added risks. Robust anatomical knowledge and meticulous surgical technique are paramount for obtaining successful resections.

Sexual Dysfunction after Clipping of Ruptured Intracranial Aneurysms.

BACKGROUND: Sexual dysfunction significantly affects interpersonal relationships and overall quality of life. It remains a matter of concern for risk assessment and counseling in patients with ruptured intracranial aneurysms. OBJECTIVE: To assess the sexual dysfunctions in patients undergoing clipping for ruptured intracranial aneurysms and comparative evaluation among different anterior circulation aneurysms. METHOD: We prospectively included 40 male patients of ruptured intracranial aneurysms of anterior circulation (age range: 20-60 years; sexually active preoperatively), managed with craniotomy and clipping. We evaluated the sexual outcome in patients with excellent Glasgow outcome score (GOS) five at a minimum one year of follow-up. Patients with GOS-5 status at follow-up were broadly classified into two groups: Anterior communicating artery aneurysm (Acom), and non-Acom) aneurysms. We valued sexual outcome with Subjective Sexual Arousal Scale for Men at follow-up, and compared in the two groups. RESULTS: Mean age of patients was 44.78 ± 9.51 years. Besides 20 Acom aneurysms, other groups included 11 middle cerebral artery aneurysms, five internal carotid artery aneurysms, three posterior communicating artery aneurysms, and one distal anterior cerebral artery aneurysm. The mean follow-up was 24.45 ± 13.58 months. Patients with non-Acom aneurysms had an overall better outcome in the sexual performance domain "P = 0.015," mental satisfaction domain "P = 0.009," and sexual assertiveness domain "P = 0.007." However, there was no statistical difference in partner communication domain "P = 0.593," and partner relationship domain "P = 0.378." Overall, the sexual outcome was inferior in patients treated for Acom aneurysms compared to other anterior circulation aneurysms. CONCLUSIONS: In cases of aneurysmal subarachnoid hemorrhage, sexual dysfunctions are common even after good clinical outcomes. The study revealed prominent differences in outcomes on the sexual quality of life in patients harboring Acom aneurysms as compared to anterior circulation aneurysms located off-midline.

General surgeon performed emergency craniotomies in regional Queensland hospitals: a 20-year state-wide study on patient outcomes.

BACKGROUND: Traumatic brain injuries account for up to 50% of trauma related deaths and if surgical intervention is indicated, consensus suggests a maximum of 4 hours to surgical decompression. The occurrence and outcomes of craniotomies performed by non-neurosurgeons in regional Queensland hospitals have never been reported previously in the literature. METHODS: A retrospective review was performed at all regional Queensland hospitals without an on-site neurosurgical service from January 2001 to December 2022 to identify patients undergoing emergency craniotomy. Data recorded included basic demographics, history of anti-coagulant use, mechanism of injury, type of haemorrhage, Glasgow Coma Score and Glasgow Outcome Scale (GOS) on discharge. Radiological parameters measured included midline shift and maximal coronal depth of haematoma. The primary aim of this study was to assess the clinical and radiological outcomes of patients who underwent a craniotomy performed by general surgeons. RESULTS: Over the past 20 years there have been 23 emergency decompressive procedures (one excluded) performed in regional Queensland. Preoperative imaging demonstrated 9 extradural haematomas and 13 subdural haematomas. Six of 17 transferred cases required reoperation after transfer to a neurosurgical centre. Survival was observed in 9 of 22 cases, with 'good' functional outcome (GOS ≥3) observed in 7 cases. In no cases were rurally performed burr holes effective. DISCUSSION: Qualitatively, a larger craniotomy may be associated with better clinical and radiological outcomes. Although rare occurrences, our results demonstrate that general surgeon performed craniotomies are frequently efficacious in producing radiological and/or clinical improvement and should be considered as a potentially lifesaving procedure.

Surgical evacuation of spontaneous cerebellar hemorrhage: Comparison of safety and efficacy of suboccipital craniotomy and robotic-assisted stereotactic hematoma drainage.

OBJECTIVE: This study compared the efficacies of robotic-assisted stereotactic hematoma drainage and suboccipital craniotomy (SC) in patients with spontaneous cerebellar hemorrhage (SCH). METHODS: This retrospective study included 138 non-comatose patients with SCH (Glasgow Coma Scale score [GCS] >8), divided into the SC and Robotic Stereotactic Assistance (ROSA) groups. The study recorded and analyzed complications and prognoses 90 days after ictus. RESULTS: The inclusion criteria were met by 138 patients: 61 in the SC and 77 in the ROSA group, with no significant differences in sex, age, GCS score, hematoma volume, and the time from ictus to operation. The time of operation was greater in the SC group (287.53±87.57) than in the ROSA group (60.54±20.03). The evacuation rate (ER) was greater in the SC group (93.20±1.58) than in the ROSA group (89.13±2.75). The incidence of pneumonia and stress ulcers, as well as the length or costs of medical services, were lower in the ROSA group than in the SC group. Ninety days after ictus, the modified Rankin Scale (mRS), Glasgow Prognostic Scale (GOS), and Karnofsky Performance Scale (KPS) scores significantly differed between the groups. The rate of good prognosis in the ROSA group was significantly higher compared with that in the SC group. The incidence of balance disorders was lower in the ROSA group than in the SC group; no statistically significant difference was found in the incidence of dysarthria and swallowing disorders. CONCLUSION: Robotic-assisted stereotactic hematoma drainage may be suitable for non-comatose and stable condition patients with SCH. This procedure improves prognosis 90 days after ictus, lowers the incidence of pneumonia and stress ulcers, and reduces the length and costs of medical services.

[Comparison of polymethyl methacrylate skull implant fixation by three types of titanium fasteners]. / Sravnenie sposobov fiksatsii implantov cherepa iz polimetilmetakrilata tremya vidami titanovykh krepezhei.

OBJECTIVE: To evaluate mechanical strength of three methods of polymethyl methacrylate skull implant fixation in two experimental models. MATERIAL AND METHODS: The first experiment was performed on a plastic model that was as close as possible to bone in structural characteristics. The second experiment was performed on a biological specimen (a ram's head). We assessed the quality of implant fixation to bone window edges by craniofixes, ties and microscrews and lateral intercortical screws. RESULTS: Craniofixes are feasible for small flat flaps, but not advisable for wide highly curved implants. They are also the most expensive method of fixation. Implant fixation by ties and microscrews is a universal method comparable in price to craniofix. Lateral intercortical fixation is effective both for small flat implants and wide implants with large curvature. However, this method is not always applicable. CONCLUSION: Combined fixation by lateral intercortical screws and ties allows for the most effective fixation while reducing the overall price of consumables.

[Surgical Simulation Using a Three-Dimensional Printer].

3D printers have been applied in bone-based surgeries, including craniofacial, plastic, oral, and orthopedic surgeries. The improved capabilities of diagnostic imaging equipment and 3D printers have enabled the development of more precise models, and research on surgical simulations and training in the field of neurosurgery is increasing. This review outlines the use of 3D printers in neurosurgery at our institution in terms of modeling methods and surgical simulations. Modeling with the powder-sticking lamination method using plaster as the material allows drilling, which is a surgical procedure. Therefore, it is useful for simulating skull base tumors, such as petrosectomy in a combined transpetrosal approach or anterior clinoidectomy in an orbitozygomatic approach. The color coding of each part of the model facilitates anatomical understanding, and meshed tumor modeling allows deep translucency. As shown above, the 3D printer's modeling ingenuity allows for useful surgical simulations for each case.

[Endoscopic Surgery for Skull Base Tumors].

With the development of endoscopic and peripheral instruments, endonasal or transcranial endoscopic surgery for skull-base tumors has become more common. Preoperative simulation makes it relatively easy to understand the anatomical relationship between skull base tumors and the surrounding vital structures, which vary with each case. This may lead to the avoidance of complications and an improvement in the removal rate. Especially in cases of skull base tumors where multiple surgical approaches are possible, the three-dimensional model can be used to confirm the surgical field for each approach and consider the most appropriate. With the development of endovascular treatment and radiotherapy, experience in craniotomy has decreased. Young neurosurgeons need to develop skills to learn as efficiently as possible from their limited experience. Therefore, it is extremely useful to provide an environment that allows for easier preoperative simulations.

[Craniotomy Clipping for Cerebral Aneurysms].

Preoperative simulation is essential to safely complete neurosurgical procedures. A vascular-oriented approach is important in cerebrovascular disorder surgery, considering anatomical variations among individuals. Particularly, subarachnoid hemorrhage surgery requires a detailed simulation of a safe dissection procedure, considering the rupture point of the aneurysm, and combined computed tomography or magnetic resonance imaging images with cerebral angiography can be useful. We present a case of subarachnoid hemorrhage and introduce the preoperative simulation performed at our hospital.

[Basic and Advanced Techniques of Anastomosis in Deep Surgical Fields:STA-SCA Anastomosis].

This article detailly describes the subtemporal-transtentorial STA-SCA bypass technique. Through temporal base drilling, copious cerebrospinal fluid evacuation before retraction, and sufficient retraction of the temporal lobe preserving the veins of the temporal base would be primodial to obtain an appropriate surgical field. Refrection of the tentrial free edge and identification of recipient SCA posterior to the entry point of the trochlear nerve into the cavernous sinus is a micro-anatomical key. Bilateral bayonet-type needle holders and forceps should be used not to shadow the surgical corridor with one's hands.