Recurrent Artery of Heubner Guiding the Clip Application for Internal Carotid Artery Bifurcation Aneurysm: 2-Dimensional Operative Video.

Aneurysms of the bifurcation of the internal carotid artery (ICA) represent approximately 5% of intracranial aneurysms and tend to occur in younger patients.1-3 They typically have a superior orientation, in close relationship with the medial (branches of the anterior cerebral artery, segment A1) and lateral (branches of the middle cerebral artery, segment M1) lenticulostriate arteries (LSA), including recurrent artery of Heubner (RAH). RAH commonly originates in the junction of A1 and A2, courses medially to laterally between LSA and anterior cerebral artery, ICA bifurcation, and middle cerebral artery before entering the lateral portion of the anterior perforated substance.4-7 Damage to these arteries are catastrophic. This complex vascular anatomy makes treatment challenging, either endovascular or microsurgical.8-13 We present a video case of microsurgical clipping for the left ICA bifurcation aneurysm. This study was approved by the ethics committee of our institution. The patient, a 46-year-old man, was diagnosed with an unruptured ICA bifurcation aneurysm during workup for intermittent headache. Morphological characteristics of the aneurysm supported intervention over conservative treatment. Digital subtraction angiography showed a prominent proximal RAH crossing between the aneurysm neck and LSA, providing anatomical protection for clip application. Microsurgical clipping was chosen, and the procedure went uneventfully. The patient consented to the procedure and to the publication of his/her image. We discussed and demonstrated throughout the video how we used this anatomic variation and trajectory of the RAH to prevent clipping of LSA unwittingly and achieve complete occlusion of the aneurysm neck.

Microneurosurgical anatomy of the basal cisterns: A brief review for cisternostomy.

Background: Cisternostomy is a surgical technique thought of and developed as an option for severe brain trauma treatment. It demands a particular knowledge and skill to microsurgically approach basal cisterns and effectively manipulate their contents. To perform this procedure safely, the anatomy and pathophysiology must be clearly understood. Methods: Detailed microscopic dissection and anatomical review were done, after a detailed reading of facts and recent publications about cisternostomy. Cisternal pathways and landmark planning are described and augmented using a new method to show de arachnoid borders. Finally, a brief discussion is written as a synopsis. Results: Cisternostomy requires thorough microscopic knowledge and microsurgical skills. This paper intends to provide information to understand better the anatomy related, thus, easing the learning curve. The technique used to show arachnoid borders, complementing cadaveric and surgical images, was useful for this purpose. Conclusion: To perform this procedure safely, it is mandatory to handle microscopic details of cistern anatomy. Reaching a core cistern is necessary to assure effectiveness. This procedure needs, as well, surgical step-by-step landmark planning and performing. Cisternostomy could be a life-saving procedure and a new powerful tool for severe brain trauma treatment. Evidence is being collected to support its indications.

Virtual preoperative planning and 3D tumoral reconstruction with Horos open-source software.

Background: Presurgical three-dimensional (3D) reconstructions allow spatial localization of cerebral lesions and their relationship with adjacent anatomical structures for optimal surgical resolution. The purpose of the present article is to present a method of virtual preoperative planning aiming to enhance 3D comprehension of neurosurgical pathologies using free DICOM image viewers. Case Description: We describe the virtual presurgical planning of a 61-year-old female presenting a cerebral tumor. 3D reconstructions were created with the "Horos®" Digital Imaging and Communications in Medicine viewer, utilizing images obtained from contrast-enhanced brain magnetic resonance imaging and computed tomography. The tumor and adjacent relevant structures were identified and delimited. A sequential virtual simulation of the surgical stages for the approach was performed with the identification of local gyral and vascular patterns of the cerebral surface for posterior intraoperative recognition. Through virtual simulation, an optimal approach was gained. Accurate localization and complete removal of the lesion were achieved during the surgical procedure. Virtual presurgical planning with open-source software can be utilized for supratentorial pathologies in both urgent and elective cases. Virtual recognition of vascular and cerebral gyral patterns is helpful reference points for intraoperative localization of lesions lacking cortical expression, allowing less invasive corticotomies. Conclusion: Digital manipulation of cerebral structures can increase anatomical comprehension of neurosurgical lesions to be treated. 3D interpretation of neurosurgical pathologies and adjacent anatomical structures is essential for developing an effective and safe surgical approach. The described technique is a feasible and accessible option for presurgical planning.

Micromirrors in Neurosurgery: Technical Overview and Benefits Assessment.

AIM: To weight the benefits and limitations of intraoperative use of micromirrors in neurosurgery. MATERIAL AND METHODS: Surgical cases where micromirrors were employed were retrospectively selected from the surgical database of five different surgeons in different hospitals. Complications directly attributable to the micromirrors were assessed intraoperatively and confirmed with postoperative neuroimaging studies. RESULTS: Fourteen patients were selected. The site of the lesion was as follows: posterior fossa (43%), frontal lobe (22%), temporal lobe (14%), parietal lobe (7%), insula (7%), and basal ganglia (7%). Five tumors (35%) were gliomas, 3 (21%) epidermoid, and 3 (21 %) supratentorial metastases. Two patients underwent microvascular decompression for neurovascular conflict, and 1 harbored a brain arteriovenous malformation. A gross total resection was achieved in all the tumors and the AVM, while an effective decompression was successfully performed in both patients with conflict. No complications directly attributable to the use of the micromirror occurred. A relatively easy learning curve was noted. CONCLUSION: Micromirrors proved to be useful in enhancing the visualization of neurovascular structures and pathology residuals within deep-seated surgical fields without the need for fixed brain retraction. Their cost-effectiveness and easy learning curve constitute solid reasons for advocating a revitalization of this ?old but gold? tool in neurosurgery.

Microneurosurgical management of aneurysms of the A1 segment of the anterior cerebral artery: Anatomy and surgical technique.

Background: Aneurysms of the A1 segment of the anterior cerebral artery (ACA) are rare and have characteristics differentiating them from other intracranial aneurysms. Their microsurgical management is challenging and requires different strategies. In this article, we review the surgical anatomy of the A1 segment of the ACA with cadaveric dissections and describe the microsurgical management of complex A1 aneurysms with illustrative cases. Methods: A right pterional craniotomy and Sylvian dissection were performed on a formalin-fixed and silicone-injected cadaver head to depict the key anatomic structures and surgical corridors for microsurgical clipping of A1 segment aneurysms. The microneurosurgical management of ruptured and unruptured aneurysms of the A1 segment of the ACA is described with case illustrations. Results: The A1 segment of the ACA can be subdivided into proximal, middle, and distal subsegments, the former having abundant perforating branches. Both patients treated with microsurgical clipping had excellent and durable outcomes and postoperative cerebral angiograms showed complete aneurysm occlusion. Conclusion: Small A1 aneurysms may require early treatment as their rupture risk appears to be higher. A1 aneurysms are usually embedded in perforators, especially those arising from the proximal A1 subsegment, and require careful distal to proximal microdissection and strategic placement of the aneurysm clip blades. The approach, arachnoid dissection, and angles of attack are carefully planned after accounting for the aneurysm dome projection, precise location of the aneurysm neck and perforators, and the presence or absence of subarachnoid hemorrhage.

Anatomic variations of the floor of the third ventricle: Surgical implications for endoscopic third ventriculostomy.

Background: Endoscopic third ventriculostomy (ETV) is currently used as a treatment for different types of hydrocephalus. However, the anatomical endoscopic variants of the third ventricle floor (3VF), as well as their surgical implications, have been underrated. The anatomic variations of the 3VF can influence the technique and the success rate of the ETV. The purpose of this article is to describe the anatomical variations of 3VF, assess their incidence, and discuss the implications for ETV. Methods: Intraoperative videos of 216 patients who underwent ETV between January 2012 and February 2020 at Hospital Infantil Universitario de San José, Bogotá, Colombia were reviewed. One hundred and eighty patients who met the criteria to demonstrate the type of 3VF were selected. Results: 3VF types were classified as follows: (1) Thinned, (2) thickened, (3) partially erased, (4) globular or herniated, and (5) narrowed. Conclusion: Knowledge of anatomical variations of the 3VF is paramount for ETV and it influences the success rate of the procedure.

Classification and Management of Pontecerebellar-Petrosal Bridging Veins.

OBJECTIVES: The risks and benefits of coagulating intradural venous elements during a retrosigmoid approach for trigeminal neurovascular decompression has not been accurately established. The objectives of this study were to identify the veins that drain into the superior petrosal sinus, classify them in relation to the suprameatal tubercle, and determine the implication of their coagulation. METHODS: A retrospective study of 3-dimensional surgical videos of retrosigmoid approaches for trigeminal neurovascular decompression from the Laboratory of Neurosurgical Innovations of Tucumán (LINT) digital archive was carried out. The veins encountered were classified into 3 groups: retromeatal, meatal and premeatal. The neurosurgical postoperative complication scale proposed by Landriel et al. was utilized to assess complications from venous coagulation. A grade 0 was added for patients without complications. The STATA 14 program was utilized for statistical analysis. RESULTS: The pontocerebellar-petrosal veins of 28 patients who underwent trigeminal decompressive surgery were analyzed. In 7 cases these were found in the retromeatal region; 100% were sacrificed. Eleven cases revealed veins within the meatal region; 90.91% were coagulated. Veins in the premeatal region were found in 14 cases; 57.14% were sacrificed. In the postoperative follow-up, 27 patients were grade 0 and 1 patient developed postoperative meningitis (grade Ib complication). No patient suffered vascular complications. CONCLUSIONS: The venous elements identified in trigeminal neurovascular decompressive surgery are variable. We propose classifying them into retromeatal, meatal, and premeatal groups. Retromeatal and meatal veins can be safely sacrificed for appropriate visualization of the neurovascular conflict. The premeatal venous elements should be coagulated only in justified cases.

Supracerebellar Transtentorial Approach for Posterior Temporomesial Cavernoma: 3-Dimensional Operative Video.

The temporomesial region is a frequent site of neurosurgical lesions such as tumors, cavernomas, or arteriovenous malformations. This region has been divided into 3 regions: anterior, middle, and posterior.1-4 The objective of Video 1 is to present the case of a posterior temporomesial cavernoma resection through a supracerebellar transtentorial approach, highlighting the surgical technique. The case is a 50-year-old female with history of temporomesial bleeding, headaches, and seizures refractory to medical treatment. In the neuroimaging studies a posterior temporomesial image was diagnosed. We selected a paramedian supracerebellar transtentorial approach in semisitting position for the surgery. With the use of neuronavigation guidance, the cavernoma was located and removed in 1 piece. The patient evolved favorably, without neurologic deficit, improving the symptoms after surgery. The approach is an excellent alternative for exposing the temporomesial region, and the semisitting position facilitates the retraction by gravity of the cerebellum, maintaining a clean surgical field during the microsurgical procedure.3-5.

Major Trauma in Elderly Patients: Worse Mortality and Outcomes in an Italian Trauma Center.

INTRODUCTION: Major trauma is the leading cause of mortality in the world in patients younger than 40 years. However, the proportion of elderly people who suffer trauma has increased significantly. The purpose of this study is to assess the correlation of old age with mortality and other unfavorable outcomes. METHODS: We assessed on one hand, anatomical criteria such as ISS values and the number of body regions affected, on the other hand, hemodynamic instability criteria, various shock indices, and Glasgow Coma Scale. Finally, we also evaluated biochemical parameters, such as lactate, BE, and pH values. We conducted a prospective and monocentric observational study of all the patients referred to the Emergency Department of the IRCCS Fondazione Policlinico S. Matteo in Pavia for major trauma in 13 consecutive months: January 1, 2018-January 30, 2019. We compared the elderly population (>75 years) and the younger population (≤75). RESULTS: We included 501 patients, among which 10% were over the age of 75 years. The mortality rate was higher among the older patients than among the younger (4% vs. 1.33%; P = 0.050). Hemodynamic instability was more common in the older patients than in the younger (26% vs. 9%; P < 0.001). More older patients (44%) had an ISS >16, in comparison with 32% of younger patients (P = 0.01). CONCLUSIONS: The elderly showed worse outcomes in terms of mortality, hospitalization rate, hemodynamic instability criteria, and anatomical and biochemical parameters.

Hand-assisted laparoscopic vs. mini-laparotomy technique for ventriculoperitoneal shunt. A meta-analysis of three thousand patients.

BACKGROUND: Whether or not the laparoscopic technique has substantial advantages over the mini-laparotomy one for ventriculoperitoneal shunt is still controversial. The present study is a literature review and a meta-analysis about this topic, focused on the duration of surgery, length of stay (LOS), infection rate and rate of distal catheter failure. METHODS: An extensive online literature search was performed, followed by a meta-analysis implemented with RevMan 5.0 Cochrane software. For laparoscopy and mini-laparotomy group, odds ratio (OR) and 95% confidence interval (CI) was calculated for distal catheter malposition/obstruction and infection rate. Mean difference was considered for duration of surgery and LOS. Fixed-effect model with a significance < 0.05 was employed. A t-test (p< 0.05) between the groups, also including the non-comparative cohort studies, was performed for each primary endpoint. RESULTS: 18 studies, involving 3361 patients, were selected. Average level of evidence was 3.2 ± 0.7. Primary shunts were 93 % in laparoscopy group and 87 % in mini-laparotomy one (p=0.626). A previous abdominal surgery was present in 37.5 % and 33.7% of laparoscopy and laparotomy group, respectively (p=0.449). Laparoscopy had a lower incidence of distal catheter failure (OR 0.52, 95% CI 0.38-0.72; p<0.001). No differences were revealed about the duration of surgery, LOS and infection rate. CONCLUSION: Laparoscopic technique has a lower risk of distal catheter failure in ventriculoperitoneal shunt for the treatment of hydrocephalus. Duration of surgery, LOS and infection rate are independent by the surgical technique. The overall level of evidence is low, and no absolute conclusions can be drawn. KEY WORDS: Hand-Assisted Laparoscopy, Hydrocephalus, Meta-Analysis, Mini-Laparotomy, Shunt Failure, Shunt Malfunction, Ventriculoperitoneal Shunt.

Subaxial Vertebral Artery Rotational Occlusion Syndrome: An Overview of Clinical Aspects, Diagnostic Work-Up, and Surgical Management.

Extrinsic compression of the subaxial vertebral artery (VA) may cause rotational occlusion syndrome (ROS) and contribute to vertebrobasilar insufficiency potentially leading to symptoms and in severe cases, to posterior circulation strokes. The present literature review aimed to report the main clinical findings, diagnostic work-up, and surgical management of the subaxial VA-ROS, the diagnosis of which can be difficult and is often underestimated. An illustrative case is also presented. A thorough literature search was conducted to retrieve manuscripts that have discussed the etiology, diagnosis, and treatment of ROS. Total 41 articles were selected based on the best match and relevance and mainly involved case reports and small cases series. The male/female ratio and average age were 2.6 and 55.6±11 years, respectively. Dizziness, visual disturbances, and syncope were the most frequent symptoms in order of frequency, while C5 and C6 were the most affected levels. Osteophytes were the cause in >46.2% of cases. Dynamic VA catheter-based angiography was the gold standard for diagnosis along with computed tomography angiography. Except in older patients and those with prohibitive comorbidities, anterior decompressive surgery was always performed, mostly with complete recovery, and zero morbidity and mortality. A careful neurological evaluation and dynamic angiographic studies are crucial for the diagnosis of subaxial VA-ROS. Anterior decompression of the VA is the cure of this syndrome in almost all cases.

A 3D printed custom-made mask model for frameless neuronavigation during retrosigmoid craniotomy. A preclinical cadaveric feasibility study.

BACKGROUND: A 3D printing custom-made mask model was tested in terms of feasibility and accuracy for frameless neuronavigation during retrosigmoid approach. METHODS: A virtual 3D model of a cadaveric injected head was obtained from a high-resolution Computed Tomography (CT) scan and 3D Printed (3DP). The course of the transverse and sigmoid sinus was marked. A transparent custommade 3DP mask model was created as a cast of 3D model. The area of the lateral sinuses was grooved to allow the surgeon to use the mask as a template to draw the course of the sinuses on the patient skull. A right retrosigmoid approach was performed on formalin-fixed injected cadaveric head. Inion and other conventional landmarks were used to mark the course of the sinuses. 3DP mask was used to re-mark the course of the sinuses. The mismatch between the landmarks-based and 3DP mask-based track was assumed as a measure of the accuracy of the 3DP mask model. RESULTS: 3DP mask model resulted precise, feasible, easy and fast to use. A perfect interlocking with the retrosigmoid area was noted. Mismatch between the landmarks-based and 3DP mask-based track was of 4 and 6 mm for transverse and sigmoid sinus, respectively. CONCLUSION: 3DP custom-made mask model is feasible, easily reproducible and reliable for the implementation of a frameless neuronavigation during retrosigmoid approach. Its accuracy is greater than that of the bone landmark neuronavigation. In selected cases, 3DP mask can be a valid option to image-guided optical or electromagnetic tracking systems. KEY WORDS: 3D Printing, Neuronavigation, Retrosigmoid Approach, Sigmoid Sinus, Transverse Sinus.

A 3D printed custom-made mask model for frameless neuronavigation during retrosigmoid craniotomy. A preclinical cadaveric feasibility study.

BACKGROUND: A 3D printing custom-made mask model was tested in terms of feasibility and accuracy for frameless neuronavigation during retrosigmoid approach. METHODS: A virtual 3D model of a cadaveric injected head was obtained from a high-resolution Computed Tomography (CT) scan and 3D Printed (3DP). The course of the transverse and sigmoid sinus was marked. A transparent custommade 3DP mask model was created as a cast of 3D model. The area of the lateral sinuses was grooved to allow the surgeon to use the mask as a template to draw the course of the sinuses on the patient skull. A right retrosigmoid approach was performed on formalin-fixed injected cadaveric head. Inion and other conventional landmarks were used to mark the course of the sinuses. 3DP mask was used to re-mark the course of the sinuses. The mismatch between the landmarks-based and 3DP mask-based track was assumed as a measure of the accuracy of the 3DP mask model. RESULTS: 3DP mask model resulted precise, feasible, easy and fast to use. A perfect interlocking with the retrosigmoid area was noted. Mismatch between the landmarks-based and 3DP mask-based track was of 4 and 6 mm for transverse and sigmoid sinus, respectively. CONCLUSION: 3DP custom-made mask model is feasible, easily reproducible and reliable for the implementation of a frameless neuronavigation during retrosigmoid approach. Its accuracy is greater than that of the bone landmark neuronavigation. In selected cases, 3DP mask can be a valid option to image-guided optical or electromagnetic tracking systems. KEY WORDS: 3D Printing, Neuronavigation, Retrosigmoid Approach, Sigmoid Sinus, Transverse Sinus.

An underrated copmlication of the organs' transplantations

INTRODUCTION: Tacrolimus is routinely used to prevent rejection after organs' transplantation. Neurotoxicity is underrated side effect, where no typical clinical, radiological, or histopathological patterns have yet been found. The present study is targeted to a review of the literature on tacrolimus-induced neurotoxicity secondary to organs' transplantation, aimed to its prompt diagnosis. MATERIALS AND METHODS: Multiple PubMed searches were performed to review relevant articles regarding tacrolimusinduced neurotoxicity. An illustrative case is also presented. RESULTS: Twenty articles published between 1997 and 2019 were identified and reviewed. Clinical manifestations of tacrolimus-induced neurotoxicity varied. MRI showed subcortical white matter involvement in most cases. Symptoms and radiological signs occurred at various drug dosages and blood tacrolimus levels. Tacrolimus discontinuation resulted in disappearance or marked reduction of neurological symptoms and imaging lesions in every case. CONCLUSION: Neurotoxicity is an underrated reversible side effect of chronic tacrolimus administration after organs' transplantation. Its prompt diagnosis, based on T2 and FLAIR MRI sequences neuroimaging combined with stereotactic biopsy, allows the discontinuation of the drug and a recovery of the patient in most of the cases. KEY WORDS: Stereotactic Biopsy, Neurotoxicity, Tacrolimus, Transplant Complications, Transplantation, Tumorlike Lesion.

Hindbrain-related syringomyelia and raised intra-abdominal pressure: implications for safety of laparoscopic and robotic surgery.

BACKGROUND: The causative role played by intra-abdominal pressure (IAP) in the syringogenesis of the Chiari 1 malformation syringomyelia has been still not adequately studied. The aim of this study is to validate the transmedullary theory about the hindbrain-related syrinx, also discussing the implications for safety of these patients related to the use of high-pressure CO2 pneumoperitoneum during laparoscopic and robotic surgery. METHODS: Fourteen patients with a hindbrain-related syrinx were candidate for a posterior fossa decompression. Preoperative and follow-up protocol involved conventional T1/T2 and cardiac-gated Cine phase-contrast MRI sequences. Peak systolic and diastolic velocities were acquired at four Regions Of Interests (ROI), namely syrinx, ventral and dorsal cervical subarachnoid space, and foramen magnum region. Data were reported as mean ± SD. Patients were followed for three years. One-way ANOVA with Bonferroni post hoc test of multiple comparisons were performed, where p-value was <0.001. RESULTS: A systolic-diastolic pulsatile pattern of CSF was found in all cases inside the syrinx. Syrinx and premedullary cistern velocities decreased within the first month after surgery (<0.001). All symptoms apart from atrophy and spasticity improved. These data lead to validate the Oldfield and Heiss transmedullary theory about syringogenesis, within which an increased IAP play a key role. CONCLUSION: Raised IAP plays a paramount role in the formation and maintenance of the hindbrain-related syrinx. High-pressure CO2 surgical pneumoperitoneum is strongly discouraged in these patients because at risk of rapid neurological worsening. A low-pressure insufflation technique has a rationale in those patients having smaller or incidental syrinxes. KEY WORDS: Hindbrain-Related Syringomyelia, Intra-Abdominal Pressure, Laparoscopic Robotic Surgery.