SupraPetrous InfraTemporal Approach: A Supplemental Approach to Supracerebellar Infratentorial for Inferior Amygdala and Hippocampal Head Access-A Cadaveric Study With Case Illustrations.

BACKGROUND AND OBJECTIVES: Access to the amygdala and hippocampus (A/H) is complex. To address the limitations and invasiveness of traditional approaches, including the Transsylvian, Subtemporal, and Supracerebellar infratentorial approaches, we developed the suprapetrous infratemporal (SPIT) approach. This study describes the nuances of this approach in both cadaveric studies and clinical cases. METHODS: Three unilateral exposures were performed using microscopic and endoscopic methodologies in the SPIT approach. After cadaveric investigation, this approach was successfully implemented in representative clinical cases. RESULTS: The SPIT approach enabled direct access to the inferior A/H, circumventing the requirement for temporal lobe retraction and detachment of the temporal lobe from the dura through a subtemporal route by drilling the upper part of the mastoid, consequently mitigating tension on the vein of Labbé. This enabled a bottom-up view because one would gain with a zygomatic osteotomy and forward projection like a mini-posterior petrosal view by using a transmastoid view, without cutting down the zygomatic arch and opening the dura subtemporally, limiting patient pain and preventing case comorbidity. The SPIT approach was performed in 2 cases of mesial temporal cavernoma presenting with seizures. The lesion was visualized intraoperatively and was successfully removed in these cases. The postoperative course was excellent with no complications, and gross total resection was radiographically confirmed with Engel Class 1a seizure freedom. CONCLUSION: The SPIT approach is a complementary approach for inferior A/H disease, combining the combined middle fossa approach modified for intradural pathology. Limited drilling of the upper aspect of the mastoid with a medial dural opening at the level of the arcuate eminence provides a direct trajectory with minimal brain retraction. Additional research encompassing a larger patient cohort and extended follow-up periods is required to substantiate the advantages of SPIT in the management of inferior A/H lesions.

Trigeminal Microvascular Decompression and Meckel's Cave Tumor Resection via Retrosigmoid Approach With Suprameatal Extension: 2-Dimensional Operative Video.

The leading cause of trigeminal neuralgia (TGN) relies on the microvascular conflict between the superior cerebellar artery (SCA) loop and the dorsal root entry zone of the trigeminal nerve (TN). However, lesions along the TN have been described as a possible cause of TGN for direct mass effect or indirect vascular transposition. Thus, the surgical approach to TGN in patients harboring cerebellopontine angle or Meckel's cave tumor should be methodically chosen. The retrosigmoid (RS) approach with suprameatal extension offers direct access to the TN in both its cisternal and Meckel's cave segment, allowing optimal TN decompression from vascular and tumoral components. Although the RS approach with suprameatal extension has been described in numerous studies,1-4 videos detailing its key steps in addressing a multicomponent TGN are lacking. In this video, we highlight the case of a 46 year-old woman with 6 months of medically refractory typical TGN with a right en plaque meningioma involving the petrous bone, petroclival junction, Meckel's cave, and tentorium. In addition, magnetic resonance imaging was suspicious for a compressive SCA loop over the dorsal root entry zone. The patient underwent a RS approach with suprameatal extension for subtotal resection of the tumor and microvascular decompression of the TGN. The patient recovered with no complications and TGN resolved.

Feasibility of exoscopic keyhole surgery: case series.

Keyhole approaches, performed with the endoscope, microscope, or exoscope, aim to minimize tissue traumatization while maximizing surgical view. The exoscope can provide better ergonomics than the microscope without restricting the space inside of the keyhole, as when using the endoscope. However, a frequently quoted reason for intraoperative exoscope-to-microscope conversion is the absence of sufficient light. In this video, the authors present 4 patients who underwent posterior fossa keyhole surgery without intraoperative conversion. The surgical objective was achieved in all patients without associated morbidity. After adequate adaptation, the exoscope allows sufficient light in the surgical field to perform safe keyhole surgery. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23116.

The Inaugural "Century" of Mixed Reality in Cranial Surgery: Virtual Reality Rehearsal/Augmented Reality Guidance and Its Learning Curve in the First 100-Case, Single-Surgeon Series.

BACKGROUND AND OBJECTIVE: Virtual reality (VR) refers to a computer-generated three-dimensional space in which a surgeon can interact with patient-specific anatomic models for surgical planning. Augmented reality (AR) is the technology that places computer-generated objects, including those made in VR, into the surgeon's visual space. Together, VR and AR are called mixed reality (MxR), and it is gaining importance in neurosurgery. MxR is helpful for selecting and creating templates for an optimal surgical approach and identifying key anatomic landmarks intraoperatively. By reporting our experience with the first 100 consecutive cases planned with VR and executed with AR, our objective is to detail the learning curve and encountered obstacles while adopting the new technology. METHODS: This series includes the first 100 consecutive complex cranial cases of a single surgeon for which MxR was intended for use. Effectiveness of the VR rehearsal and AR guidance was analyzed for four specific contributions: (1) opening size, (2) precise craniotomy placement, (3) guidance toward anatomic landmarks or target, and (4) antitarget avoidance. Seventeen cases in the study cohort were matched with historical non-MxR cases for comparison of outcome parameters. The cases in which MxR failed were plotted over time to determine the nature of the "learning curve." RESULTS: AR guidance was abandoned in eight operations because of technical problems, but problem-free application of MxR increased between the 44th and 63rd cases. This provides some evidence of proficiency acquisition in between. Comparing the 17 pairs of matched MxR and non-MxR cases, no statistically significant differences exist in the groups regarding blood loss, length of stay nor duration of surgery. Cases where MxR had above-expectation performances are highlighted. CONCLUSION: MxR is a powerful tool that can help tailor operations to patient-specific anatomy and provide efficient intraoperative guidance without additional time for surgery or hospitalization.

Volumetric Resection and Complications in Nonfunctioning Pituitary Adenoma by Fully Endoscopic Transsphenoidal Approach along 15 Years of Single-Center Experience.

Objective The aim of this study was to evaluate the rate of complications and the extent of resection (EOR) of nonfunctioning pituitary adenomas by endoscopic endonasal approach (EEA) in a 15-year learning curve. Methods A total of 100 patients operated by the same surgical team were divided chronologically into two, three, and four groups, comparing differences in EOR measured by a semiautomatic software (Smartbrush, Brainlab), rate of immediate postoperative complications, and the visual and hormonal status at 6 months. Results There were no significant differences over the years in rates of postoperative complications and in visual status at 6 months. A significant linear correlation between the EOR and the number of surgeries (rho = 0.259, p = 0.007) was found. The analysis was performed in three groups because of the remarkable differences among them; the EOR were: 87.2% (early group), 93.03% (intermediate group), and 95.1% (late group) ( p = 0.019). Gross total resection was achieved in 30.3, 51.5, and 64%, respectively ( p = 0.017); also, the rate of reoperation and the worsening of at least one new hormonal axis were worse in the early group. Consequently, the early group had a higher risk of incomplete resection compared with the late group (odds ratio: 4.2; 95% confidence interval: 1.5-11.7). The three groups were not different in demographic and volume tumor variables preoperatively. Conclusions The first 33 interventions were associated with a lower EOR, a high volume of residual tumor, a high reoperation rate, and a higher rate of hormonal dysfunction. We did not find differences in terms of postoperative complications and the visual status at 6-month follow-up.

Beyond Classic Anastomoses Training Models: Overview of Aneurysm Creation in Rodent Vessel Model.

Nowadays, due to the decline in the number of microsurgical clippings for cerebral aneurysms and revascularization procedures, young neurosurgeons have fewer opportunities to participate and train on this type of surgery. Vascular neurosurgery is a demanding subspecialty that requires skills that can only be acquired with technical experience. This background pushes the new generations to be ready for such challenging cases by training hard on different available models, such as synthetic tubes, chicken wings, or placenta vessels. Although many training models for vascular neurosurgery have been described worldwide, one of the best is the rodent vessels model. It offers pulsation, coagulation, and real blood flow conditions in a physiologic atmosphere that mimics perfectly the intracranial human vessels environment, especially in terms of size. However, the current differences in governmental different regulations about the use of living animals in medical experimentation and the social awareness, as well as the lack of financial support, cause more difficulties for neurosurgeons to start with that kind of training. In this review, we describe the tools and techniques as basic steps for vascular microsurgery training by using rodent models, that provide an accurate copy of brain vessels environment under stable conditions. The initial three classical known microanastomoses for neurosurgeons are end-to-end, end-to-side, and side-to-side, but in literature, there have been described other more complex exercises for training and investigation, such as aneurysm models. Although there is still little data available, we aim to summarize and discuss aneurysm's training models and reviewed the current literature on the subject and its applications, including a detailed description of the techniques.

Treatment of cervical myelopathy by posterior approach: Laminoplasty vs. laminectomy with posterior fixation, are there differences from a clinical and radiological point of view?

INTRODUCTION: Cervical degenerative myelopathy is a variable and progressive degenerative disease caused by chronic compression of the spinal cord. Surgical approaches for the cervical spine can be performed anteriorly and/or posteriorly. Regarding the posterior approach, there are 2 fundamental techniques: laminoplasty and laminectomy with posterior fixation (LPF). There is still controversy concerning the technique in terms of outcome and complications. The aim of the present work is to analyze from the clinical and radiological point of view these 2 techniques: laminoplasty and LPF. MATERIALS AND METHODS: A historical cohort of 39 patients was reviewed (12 LFP and 27 laminoplasty) including patients operated in a 10 years period at the Hospital Universitario La Paz with a follow-up of 12 months after surgery was carried out. The clinical results were analyzed and compared using the Nurick scale and the modified Japanese Orthopaedic Association Scale (mJOA) and the radiological results using the Cobb angle, Sagittal Vertical Axis, T1 Slope and alignment (measured by Cobb-T1 Sloppe). RESULTS: Significant differences were observed in the postoperative improvement of the Nurick scale (p = 0.008) and mJOA (p = 0.018) in the laminoplasty group. In LFP there is a tendency to a greater improvement, but statistical significance is not reached due to the low sample size of this group. No statistically significant differences were observed in the radiological variables. Regarding the total number of complications, a higher number was observed in the laminoplasty group (7 cases) versus LFP (one case), but no statistically significant differences were observed. CONCLUSIONS: Laminoplasty and LFP are both safe and effective procedures in the treatment of cervical degenerative myelopathy. The findings of our study demonstrate statistically significant clinical improvement based on the Nurick and mJOA scales with laminoplasty. No significant differences in terms of complications or radiological variables were observed between the 2 techniques.

Case Report: Decompressive Craniectomy for COVID-19 Malignant Cerebral Artery Infarction. Is Surgery a Good Option?

SARS-CoV2 infection can lead to a prothrombotic state. Large vessel occlusion, as well as malignant cerebral stroke have been described in COVID-19 patients. In the following months, given the increase in COVID-19 cases, an increase in malignant cerebral SARS-CoV2 associated strokes are expected. The baseline situation of the patients as well as the risk of evolution to a serious disease due to the virus, depict a unique scenario. Decompressive craniectomy is a life-saving procedure indicated in patients who suffer a malignant cerebral stroke; however, it is unclear whether the same eligibility criteria should be used for patients with COVID-19. To our knowledge seven cases of decompressive craniectomy and malignant cerebral stroke have been described to date. We report on a 39-year-old female with no major risk factors for cerebrovascular disease, apart from oral contraception, and mild COVID-19 symptoms who suffered from left hemispheric syndrome. The patient underwent endovascular treatment with stenting and afterward decompressive craniectomy due to a worsening neurological status with unilateral unreactive mydriasis. We present the case and provide a comprehensive review of the available literature related to the surgical treatment for COVID-19 associated malignant strokes, to establish whether the same eligibility criteria for non-COVID-19 associated strokes should be used. Eight patients, including our case, were surgically managed due to malignant cerebral stroke. Seven of these patients received decompressive craniectomy, and six of them met the eligibility criteria of the current stroke guidelines. The mortality rate was 33%, similar to that described in non-COVID-19 cases. Two patients had a left middle cerebral artery (MCA) and both survived after decompressive craniectomy. Our results support that decompressive craniectomy, using the current stroke guidelines, should be considered an effective life-saving treatment for COVID-19-related malignant cerebral strokes.

Diffuse leptomeningeal glioneuronal tumour: where to biopsy? Case report and literature review.

PURPOSE: Diffuse leptomeningeal glioneuronal tumour (DLGT) is an infrequent entity. Diagnosis is made with biopsy but with so few cases described management, prognosis remains undefined. There are not currently any articles regarding most effective place to biopsy. METHODS: Current literature review and introduction of the case of a 3-year-old male presenting at the emergency room with irritability, vomiting and nuchal rigidity. A head CT was made showing tetraventricular enlargement and a posterior fossa cyst. RESULTS: Patient underwent urgent ventriculoperitoneal shunting surgery with complete symptomp resolution. Brain MRI showed diffuse leptomeningeal enhancing, predominantly in basal cisterns, and multiple cystic-solid lesions along the neural axis. After ruling other conditions, a biopsy among intraoperative samples, was obtained of a PET positive gadolinium spinal enhancing lesion at D8 level, with the final diagnosis of DLGT. CONCLUSION: DLGT can present as acute hydrocephalus. Biopsy stablishes the diagnosis but the place to take the sample can be difficult to select. Our experience suggests that PET-CT and intraoperative biopsy analysis can improve the effectivity of a representative sample.

Volumetric Study of Nonfunctioning Pituitary Adenomas: Predictors of Gross Total Resection.

OBJECTIVE: Despite the efforts made to determine the achieved resection grade after pituitary adenoma surgery, there is a high level of disagreement among all the available classifications and measurement methods used. Our objective is to identify the factors that preoperatively could predict a gross total resection (GTR) of a clinically nonfunctioning pituitary adenoma through an endoscopic endonasal approach. METHODS: Across 100 surgeries, we analyzed epidemiologic and clinical data, radiologic relevant data, extent of resection (EOR), and postoperative outcomes. The EOR was measured objectively through an accurate volumetric analysis. RESULTS: The median presurgical volume was 8.58 cm3 (range, 0.5-58 cm3), the median maximum diameter was 27.3 mm (range, 7-67 mm), and the Knosp grade was 0 in 1 patient, 1 in 23%, 2 in 31%, 3 in 23% and 4 in 22% of patients. In the multivariate logistic regression analysis, we found 3 factors that significantly predicted the chances of a successful GTR: previous sellar surgery, Knosp grade, and tumor signal in the T2-weighted magnetic resonance imaging scan. Another 10 radiologic variables were analyzed and had no effect on the EOR. CONCLUSIONS: Knosp grade (P < 0.001; odds ratio [OR], 25.65; 95% confidence interval, 7.19-91.52) is the most predictive factor for performing a GTR of nonfunctioning pituitary adenoma. Previous pituitary surgery (P = 0.023; OR, 5.81) and an isointense T2-weighted signal (P = 0.034; OR, 3.75) also negatively influenced the chances of GTR. We highlight the influence of T2-weighted signal in the chances of GTR.

Decompressive craniectomy in malignant middle cerebral artery infarction: family perception, outcome and prognostic factors. / Craniectomía descompresiva en el infarto maligno de arteria cerebral media: percepción familiar, resultados y factores pronósticos.

OBJECTIVE: The prognosis of one hemisphere malignant infarction creates doubt among neurosurgeons about decompressive hemicraniectomy indication. What results are achieved in the short to medium term? Are families satisfied with the surgery once the patient is at home? In the present study, we analyze our experience in this matter during the last thirteen years. MATERIAL AND METHODS: In our review, twenty-one patients were included from 2004 to 2017, according to the protocol for the management of ischaemic stroke that is implemented in our institution. The relatives were interviewed by telephone. The functional outcome at discharge, 3 months, 1 year, and at present was measured using the modified Rankin scale (mRS). RESULTS: Patient age was shown to be directly related to the mRS (r=0.56; p=0.035) and 37.5% achieved a good outcome (mRS≤3); 78.9% of the interviewed relatives would repeat the surgical decision. CONCLUSIONS: We present a 21 patients group where the best outcome was achieved in patients ≤60 years old. The severe neurological sequelae in patients with malignant infarction subjected to decompressive hemicraniectomy are tolerated and accepted by most families to the benefit of survival. We must not let this family satisfaction hide the prognosis, having to contextualize it within the real ambulatory situation of the patients.

Epidural Lipomatosis and Syringomyelia in Adulthood: Case Report and Literature Review.

BACKGROUND: We review 2 previously published cases of epidural lipomatosis associated with syringomyelia. We also present the case of a 42-year-old woman with a medullary syrinx from C1 to T3, initially only with upper limb paresthesias that presented after 10 years of follow-up for left hemiparesis and paresthesias in the tongue. Chiari malformation and cerebral or spinal space-occupying lesions were ruled out, as were other causes of syrinx except the presence of epidural lipomatosis extending from T1 to T12. CASE DESCRIPTION: Right laminotomies were performed from T1 to T12, removing excessive epidural fat tissue. After surgery the symptoms remained stable. At discharge the patient progressively recovered from the hemiparesis, and in follow-up magnetic resonance imaging the resolution of the syrinx was confirmed. CONCLUSIONS: This is the third case of a patient with a spinal syrinx and no other related causes except from spinal lipomatosis, although with only 3 cases it is not possible to completely state that lipomatosis caused the syrinx. Our case supports the trend established by the 2 previous cases. For treatment, initially patients should be managed conservatively, trying to correct the underlying etiologies of spinal lipomatosis. In case of failed conservative treatment, removal of adipose epidural excess in the most appropriate way is preferred.