Syringopleural shunt for refractory syringomyelia: how I do it.

BACKGROUND: Surgical treatment of syringomyelia is directed at the reconstruction of the subarachnoid space and restoration normal cerebrospinal fluid flow. Direct intervention on the syrinx is a rescue procedure and should be offered to patients with refractory syringomyelia. METHODS: We provide an overview on indications and technique of syringopleural shunt (SPS). The procedure involves the connection of syrinx with the pleural space using a lumboperitoneal shunt. The occurrence of a negative pressure inside the pleural compartment offers an appropriate gradient for drainage from the syrinx. CONCLUSIONS: The SPS allows for a safe and effective treatment of persistent syringomyelia when management of the underlying cause does not yield substantial improvement.

Diagnosis and treatment of Chiari malformation and syringomyelia in adults: international consensus document.

BACKGROUND: Syringomyelia and Chiari malformation are classified as rare diseases on Orphanet, but international guidelines on diagnostic criteria and case definition are missing. AIM OF THE STUDY: to reach a consensus among international experts on controversial issues in diagnosis and treatment of Chiari 1 malformation and syringomyelia in adults. METHODS: A multidisciplinary panel of the Chiari and Syringomyelia Consortium (4 neurosurgeons, 2 neurologists, 1 neuroradiologist, 1 pediatric neurologist) appointed an international Jury of experts to elaborate a consensus document. After an evidence-based review and further discussions, 63 draft statements grouped in 4 domains (definition and classification/planning/surgery/isolated syringomyelia) were formulated. A Jury of 32 experts in the field of diagnosis and treatment of Chiari and syringomyelia and patient representatives were invited to take part in a three-round Delphi process. The Jury received a structured questionnaire containing the 63 statements, each to be voted on a 4-point Likert-type scale and commented. Statements with agreement <75% were revised and entered round 2. Round 3 was face-to-face, during the Chiari Consensus Conference (Milan, November 2019). RESULTS: Thirty-one out of 32 Jury members (6 neurologists, 4 neuroradiologists, 19 neurosurgeons, and 2 patient association representatives) participated in the consensus. After round 2, a consensus was reached on 57/63 statements (90.5%). The six difficult statements were revised and voted in round 3, and the whole set of statements was further discussed and approved. CONCLUSIONS: The consensus document consists of 63 statements which benefited from expert discussion and fine-tuning, serving clinicians and researchers following adults with Chiari and syringomyelia.

Clinical outcome after microvascular decompression for trigeminal neuralgia: a systematic review and meta-analysis.

Microvascular decompression (MVD) is considered an effective treatment for trigeminal neuralgia (TN). However, the anatomical and clinical variables associated with a better outcome are not fully examined. The authors performed a systematic review and meta-analysis of the literature investigating the immediate and long-term clinical results of MVD for TN, and the impact of the anatomical features of the neurovascular conflict on the outcome. The systematic search of three databases was performed for studies published between January 1990 and November 2021. PRISMA guidelines were followed. Random-effects meta-analysis was used to pool the analyzed outcomes, and random-effect meta-regression was used to examine the association between the effect size and potential confounders. A funnel plot followed by Egger's linear regression was used to test publication bias. A total of 9 studies were included in this analysis, including 2102 patients with trigeminal neuralgia. The immediate post-operative rate of BNI I was 82.9%, whereas surgical failure (BNI IV-V) was reported in approximately 2.6% of patients. CSF leak was the most common postoperative complication (2.4%). The rate of BNI I at last follow up was 64.7% (p < 0.01), showing a significant negative correlation after multiple meta-regression with the rate of patients with isolated venous conflict (p < 0.01). On the other hand, the evidence of an arterial conflict proved is positive association with a favorable outcome (p < 0.01). At the last follow-up, BNI IV-V was reported in 19.2% (95% CI 8.9-29.5%, p < 0.01, I2 = 97.3%). This meta-analysis confirms the safety and efficacy of MVD for TN. The occurrence of serious postoperative complications is very low. The long-term outcome is associated with the type of vascular structure involved, being pure venous conflict associated with a higher risk of surgical failure. These findings should be considered when planning surgery for patients with TN.

Microvascular decompression for trigeminal neuralgia due to vertebrobasilar artery compression: a systematic review and meta-analysis.

Trigeminal neuralgia (TN) caused by vertebrobasilar artery (VBA) compression is a rare event, reported between 2 and 6% (Linskey et al. J Neurosurg 81:1-9,1992, Vanaclocha et al.World Neurosurg 96:516-529,2016) of the time. Microvascular decompression (MVD) is advised for drug-resistant pain and, although technically challenging, is associated with an excellent outcome in current literature (Apra et al.Neurosurg Rev 40:577-582,2017, Cruccuet al. EurJ Neurol 15:1013-1028,2008, Linskey et al. J Neurosurg 81:1-9,1992). The authors performed a systematic review and meta-analysis of the literature examining the rate of MVD for trigeminal neuralgia caused by VBA compression and the post-operative outcome. The systematic search of three databases was performed for studies published between January 1990 and October 2020. Random-effects meta-analysis was used to pool the analyzed outcomes, and random-effects meta-regression was used to examine the association between the effect size and potential confounders. Funnel plot followed by Egger's linear regression was used to test publication bias. We included 9 studies, and the overall rate of TN due to VBA compression was 3.4% (95% CI 2.5-4.3%, p < 0.01, I2 = 67.9%) among all MVD for TN. Immediately after surgery, 96% (p < 0.01, I2 = 0%) of patients were pain-free, and at last follow-up, approximately 93% (p < 0.01, I2 = 0%) of patients were classified as BNI I-II. Hearing impairment and facial numbness were the most common long-term complications ensuing MVD for VBA compression (5% and 13%, respectively). In conclusion, the surgical management of trigeminal neuralgia caused by VBA compression is associated with good outcome and low rate of post-operative complications. Further studies are needed to analyze the long-term results and the rate of pain recurrence among this population.

Unsuccessful bypass and trapping of a giant dolichoectatic thrombotic basilar trunk aneurysm. What went wrong?

Aneurysms of the basilar trunk represent an exceptional challenge to the neurosurgeon, due to high mortality and surgical morbidity. We present a 69-year-old man with a giant dolichoectatic thrombotic basilar trunk aneurysm (BTA), who underwent right orbitozygomatic craniotomy, posterior cerebral artery (PCA) to right middle cerebral artery (MCA) bypass and trapping of the BTA. Unfortunately, patient died after surgery due to multiple foci of intraparenchymal haemorrhage and thrombosis of a short segment proximal to aneurysm trapped and his body was donated to the hospital, giving us the unique opportunity to compare intraoperative details with anatomical dissection findings, according to our previously published cadaveric neurosurgical research. The great and unique opportunity of this reported case, to learn by watching and watching again what has been done during surgery, to observe small vessels and brainstem perforators and to look at stiches of the bypass, SVG and the position of the clips, permits to refine the theoretical and practical skills for the treatment of complex aneurysms such as that one reported.

Role of magnetic resonance imaging following postoperative radiotherapy in clinical decision-making of patients with high-grade glioma.

OBJECTIVES: The present study aims to investigate the role of the first magnetic resonances (MRI) following radio-chemotherapy (RT-CT) in patients diagnosed with high-grade glioma. METHODS: We retrospectively recorded radiological evaluations following RT-CT, symptoms related to disease progression (avoiding any sign due to radiotherapy or chemotherapy) and the change of therapeutic strategy. RESULTS: In March 2021, at data analysis, the data of 149 patients diagnosed with high-grade glioma and treated between May 2013 and July 2020 were retrieved for the present analysis. Two out of 122 (1.6%), 5 out of 106 (4.7%) and 8 out of 92 (8.6%) asymptomatic patients received the diagnosis of disease recurrence at the time of the first, second and third MRI, respectively. Otherwise, 16 out of 27 (59.2%), 16 out of 24 (66.6%) and 13 out of 16 (82.2%) symptomatic patients changed their therapy after the first, second and third MRI, respectively. Among patients that experienced radiological signs of distant progression, 10 out of 14 were symptomatic and changed their therapy. CONCLUSIONS: MRIs performed by 6 months after the end of RT-CT lead to change treatment strategy mostly in symptomatic patients.

Impact of temporalis muscle thickness in elderly patients with newly diagnosed glioblastoma treated with radio or radio-chemotherapy.

BACKGROUND: There is an unmet need for new biomarkers able to predict both the outcomes of up-front therapy and the compliance of elderly patients diagnosed with glioblastoma. For this purpose, temporal muscle thickness is a promising tool to be investigated. METHODS: Data from 52 glioblastoma patients older than 65 years, treated with post-operative radio or radio-chemotherapy and referred to Pisa University Hospital, were retrieved. The thickness of temporal muscle (TMT) was divided into quartiles and correlated with overall survival (Our primary endpoint). Survival curves were calculated using Kaplan-Meier method, and log-rank test was used to evaluate the differences between curves. RESULTS: Patients in the lower quartile of TMT, with TMT thinner than 7 mm, have survived longer; both univariate and multivariate analyses showed a statistically significant correlation between TMT and overall survival (P = 0.012 and P = 0.003, respectively). CONCLUSION: Future prospective and more extensive studies focused on elderly glioblastoma patients are needed to confirm the role of TMT as prognostic value on OS and to help explaining this association.

Is DAT imaging abnormality in normal pressure hydrocephalus always suggestive of degeneration?

Idiopathic normal pressure hydrocephalus (iNPH) is a debated entity with controversial pathogenesis, diagnostic criteria, and predictors of response after ventriculoperitoneal shunt (VPS). Parkinsonian signs are frequently reported in the clinical picture, sometimes due to the coexistence of an underlying neurodegenerative parkinsonism and sometimes in the absence thereof. To distinguish these two scenarios is crucial, since they may carry different long-term response to CSF drainage. 123I-FP-CIT-SPECT was believed to be helpful in this regard, however its role in predicting surgical outcome has been disputed. We illustrate a patient presented with gait disturbance, urinary incontinence, and asymmetrical parkinsonian signs, who underwent a 3T brain MRI and a 123I-FP-CIT-SPECT. VPS was performed. The patient repeated a 123I-FP-CIT-SPECT, 18 months after the operation, and was clinically followed up for 24 months. Our patient displayed clinical and radiological criteria for iNPH and an abnormal asymmetrical uptake in 123I-FP-CIT-SPECT, consistent with her asymmetrical parkinsonism. However, the organization of the substantia nigra studied with iron-sensitive sequences in 3T brain MRI scan appeared intact. The patient revealed an improvement both clinically and in 123I-FP-CIT-SPECT at postsurgical follow-up. Our report suggests that abnormal 123I-FP-CIT-SPECT may not necessarily reveal an overlap with neurodegenerative parkinsonism; its partial reversibility may suggest that the mechanical effect exerted on the striatum by ventriculomegaly ultimately leads to downregulation of dopaminergic transporters which may improve after VPS.

Radiological outcome after surgical treatment of syringomyelia-Chiari I complex in adults: a systematic review and meta-analysis.

Foramen magnum decompression (FMD) is widely accepted as the standard treatment for syringomyelia associated with Chiari type I malformation (CMI). Despite extensive clinical investigations, relevant surgical details are still matter of debate. The authors performed a systematic review and meta-analysis of the literature examining the radiological outcome of syringomyelia in adult patients with CMI after different surgical strategies. PRISMA guidelines were followed. A systematic search of three databases was performed for studies published between 1990 and 2018. Our systematic review included 13 studies with a total of 276 patients with CMI associated with syringomyelia. Overall, the rate of post-operative radiological improvement at last follow-up was 81.1% (95% CI 73.3-88.9%; p < 0.001; I2 = 71.4%). The rate of post-operative syrinx shrinkage did not differ significantly among both groups of decompression with the extra-arachnoidal technique and arachnoid dissection (90%, 95% CI 85.1-94.8%, I2 = 0% vs 79.8%, 95% CI 61.7-98%, I2 = 85.5%). A lower rate of post-operative radiological syrinx shrinkage was observed after decompression with splitting of the outer layer of the dura (55.6% 95% CI 40.5-70.8%, I2 = 0%). CSF-related complications and infections were similar among the different groups. Our meta-analysis found that FMD with the extra-arachnoidal technique and arachnoid dissection provides similar results in terms of post-operative shrinkage of syringomyelia. Patients undergoing decompression with splitting of the dura presented the lower rate of syrinx reduction. These data should be considered when choosing the surgical approach in adult patients with CMI associated with syringomyelia.

Optimal intracranial pressure in patients with aneurysmal subarachnoid hemorrhage treated with coiling and requiring external ventricular drainage.

Optimal management of intracranial pressure (ICP) among aneurysmal subarachnoid hemorrhage (aSAH) patients requiring external ventricular drainage (EVD) is controversial. To analyze predictors of delayed cerebral ischemia (DCI)-related cerebral infarction after aSAH and the influence of ICP values on DCI, we prospectively collected consecutive patients with aSAH receiving coiling and requiring EVD. Predictors of DCI-related cerebral infarction (new CT hypodensities developed within the first 3 weeks not related to other causes) were studied. Vasospasm and brain hypoperfusion were studied with CT angiography and CT perfusion (RAPID-software). Among 50 aSAH patients requiring EVD, 21 (42%) developed DCI-related cerebral infarction, while 27 (54%) presented vasospasm. Mean ICP ranged between 2 and 19 mmHg. On the multivariate analysis, the mean ICP (OR = 2, 95%CI = 1.01-3.9, p = 0.042) and the mean hypoperfusion volume on Tmax delay > 6 (OR = 1.2, 95%CI = 1.01-1.3, p = 0.025) were independent predictors of DCI. To predict DCI-related cerebral infarction, Tmax delay > 6 s presented the highest AUC (0.956, SE = 0.025), with a cutoff value of 18 ml showing sensitivity, specificity, PPV, NPV, and accuracy of 90.5% (95%CI = 69-98.8%), 86.2% (95%CI = 68.4-96%), 82.6% (95%CI = 65.4-92%), 92.5% (95%CI = 77-98%), and 88% (95%CI = 75-95%), respectively. The AUC of the mean ICP was 0.825 (SE = 0.057), and the best cutoff value was 6.7 mmHg providing sensitivity, specificity, PPV, NPV, and accuracy of 71.4% (95%CI = 48-89%), 62% (95%CI = 42-79%), 58% (95%CI = 44-70%), 75% (95%CI = 59-86%), and 66% (95%CI = 51-79%) for the prediction of DCI-related cerebral infarction, respectively. Among aSAH patients receiving coiling and EVD, lower ICP (< 6.7 mmHg in our study) could potentially be beneficial in decreasing DCI-related cerebral infarction. Brain hypoperfusion with a volume > 18 ml at Tmax delay > 6 s presents a high sensibility and specificity in prediction of DCI-related cerebral infarction.

Ventriculostomy-related hemorrhage in patients on antiplatelet therapy for endovascular treatment of acutely ruptured intracranial aneurysms. A meta-analysis.

The risk of ventriculostomy-related hemorrhage among patients requiring antiplatelet therapy (AT) for the endovascular treatment of acutely ruptured intracranial aneurysms needed further investigation. The authors performed a systematic review and meta-analysis of the literature examining the EVD-related hemorrhage rate among patients with and without AT (controls). According to PRISMA guidelines, a comprehensive review of studies published between January 1990 and April 2018 was carried out. The authors identified series with > 5 patients reporting the EVD-associated hemorrhage rate among the AT group and the control group. Variables influencing outcomes were analyzed using a random-effects meta-analysis model. We included 13 studies evaluating 516 (with AT) and 647 (without AT) patients requiring ventriculostomy. EVD-related hemorrhage rates were higher among the AT group (125/516 = 20.9%, 95% CI = 11.9-30%, I2 = 90% vs 57/647 = 9%, 95% CI = 5.5-12.5%, I2 = 45.8%) (p < 0.0001). Major EVD-associated hemorrhage rates were low in both the AT and control group (25/480 = 4.4%, 95% CI = 1.7-7.7%, I2 = 53.9% vs 6/647 = 0.7%, 95% CI = 0.03-1.7%, I2 = 0%) (p < 0.0001). Ventriculostomy before embolization and intraprocedural AT were associated with lower rates of EVD-related bleeding (32/230 = 9.6%, 95% CI = 2.1-17.1%, I2 = 75.4% vs 6/24 = 25.1%, 95% CI = 8.8-41%, I2 = 0%) (p < 0.02). The rate of major hemorrhage was higher after dual AT (CP + ASA) compared to single AT (ASA or CP) used as an intraprocedural loading dose (13/173 = 7%, 95% CI = 3.3-10.7%, I2 = 0% vs 6/210 = 1.7%, 95% CI = 0.1-3.4%, I2 = 0%) (p < 0.009). AT during endovascular treatment of acutely ruptured intracranial aneurysms increases the risk of EVD-related hemorrhages, although most of them are small and asymptomatic. When ventriculostomy is performed before endovascular procedures requiring antiplatelet administration, the hemorrhagic risk is minimized. A single antiplatelet therapy is associated with a lower rate of major bleeding than a dual therapy.

Post-operative morbidity ensuing surgery for insular gliomas: a systematic review and meta-analysis.

The surgical resection of insular gliomas remains a challenge. Middle cerebral artery perforating arteries and deep functional pathways affect the extent of resection and the rate of post-operative morbidity. The authors performed a systematic review and meta-analysis of the literature examining early and permanent post-operative deficits in patients who underwent resection of insular gliomas using awake craniotomy with direct electrical stimulation (DES) versus surgery under general anesthesia. A systematic search of three databases was performed for studies published between 1990 and 2018. Random-effect meta-analysis was used to pool the rate of early and permanent post-operative deficits. Random-effect meta-regression was used to examine the association between the rate of post-operative deficit and the anesthesia protocol. We included eight studies evaluating 227 patients with insular glioma. The rate of permanent sequelae was lower after awake craniotomy with DES (3.5% vs 15.7%; P = .001), and early deficits were lower after surgery under general anesthesia (27.3% vs 47.7%; P = .04). Awake surgery was significantly more common among patients with tumor located within the dominant hemisphere (P < .001). No significant association arose between the rates of post-operative deficits and the use of intraoperative neuronavigation and the neurophysiological monitoring. Furthermore, neither extent of resection nor tumor histology influenced the onset of permanent sequelae. Awake craniotomy with DES is associated with a significantly lower rate of permanent neurological morbidity after an early increase of transient post-operative deficits. These data support the use of awake mapping in insular glioma resection.

IDH wild-type WHO grade II diffuse low-grade gliomas. A heterogeneous family with different outcomes. Systematic review and meta-analysis.

WHO grade II diffuse low-grade gliomas (DLGGs) were recently divided into sub-groups on the basis of their molecular profiles. IDH wild-type (IDH-wt) tumors seem to be associated with unfavorable prognoses due to biological similarities to glioblastomas. The authors performed a systematic review and meta-analysis of literature examining epidemiology, clinical characteristics, management, and the outcome of IDH-wt grade II DLGGs. According to PRISMA guidelines, a comprehensive review of studies published from January 2009 to October 2017 was carried out. The authors identified series that examined the prevalence rate, clinical and radiological characteristics, treatment, and outcome of IDH-wt DLGGs. Variables influencing outcomes were analyzed using a random-effects meta-analysis model. Finally, a meta-regression analysis was performed to examine the impact of therapeutic strategies on the effect-size. Twenty-two studies were included in this systematic review. The IDH-wt prevalence rate was 22.9% (95% CI 18.4-27.4%). The hazard ratio for this molecular subgroup in the DLGGs population was 3.46 (95% CI 2.24-5.36; p < 0.001), and the heterogeneity was significant (I2 = 85%, τ2 = 0.88) (HR range 1.28-376). Nonetheless, publication bias did not affect the analysis (p = 0.176). The meta-regression revealed that the extent of resection and post-operative chemotherapy affected the outcome in the IDH-wt subgroup (p < 0.001 and 0.015, respectively), with no significant association of the HR with the rate of RT or RT + CHT. The prevalence of IDH-wt tumors is approximately 23% of DLGGs. The absence of IDH mutation is associated with a heterogeneous outcome, and its therapeutic relevance for postoperative management remains unclear. Maximal surgical resection improves the overall survival in the DLGGs population, beyond molecular status. Further molecular stratification is needed to better understand IDH-wt behavior and therapeutic response.

Petroclival meningiomas: the risk of post-operative cranial nerve deficits among different surgical approaches-a systematic review and meta-analysis.

BACKGROUND: The surgical resection of petroclival meningiomas (PCMs) remains a challenge. Both the relationship with neurovascular structures and the deep location of the tumor can affect the extent of resection and the rate of post-operative morbidity. METHODS: The authors performed a systematic review and meta-analysis of the literature examining the rate of new cranial nerve (CN) deficits after resection of PCM. A systematic search of two databases was performed for studies published between 1990 and 2018. Random-effect meta-analysis was used to pool the rate of post-operative CN deficits, mortality rate, and rate of radical resection. RESULTS: We included twelve studies and 334 patients harboring PCM. The overall rate of complete resection was 68% (95% CI 57.9-78.2%; p < 0.01; I2 = 83%). The rate of early and late post-operative CN deficits was the following: 3.8 and 2.7% (III CN), 6.6 and 3% (IV), 7.3 and 5.5% (V CN), 8 and 3.6% (VI CN), 8.9 and 8.9%% (VIII), and 4 and 2.7% (IX-XI CNs) (I2 = 0%, and p < 0.01 for all analyses). The risk of post-operative deficit of the IV CN was higher among the petrosal group (7.6%; I2 = 0% vs 2.1%; I2 = 0%), whereas the impairment of VII CN function was higher among retrosigmoid group (16.6%; I2 = 64.6% vs 11.4%; I2 = 52.8%), but it was transient in the majority of cases. CONCLUSIONS: This systematic review and meta-analysis provides a detailed overview of post-operative CN deficits ensuing surgical resection of PCMs. These findings should be acknowledged when counseling patients with PCMs regarding the more appropriate approach for their tumor.

Arterial aneurysms associated with intracranial dural arteriovenous fistulas: epidemiology, natural history, and management. A systematic review.

Arterial aneurysms are uncommon among patients with dural arteriovenous fistulae (DAVFs), and there is limited information available to guide treatment decisions in such cases. We performed a systematic review of the literature, including a case of a DAVF associated with a flow-related intraorbital ophthalmic artery (OA) aneurysm that we have recently managed. The purpose of our study was to clarify epidemiology, natural history, and management of these lesions. A total of 43 published cases of DAVF associated aneurysms were found in 26 studies on the topic. Anterior cranial fossa was the most common location (40%), and ethmoidal branches were the most common arterial feeders (55%). In about 63% of cases, the aneurysm was located on artery unrelated to DAVF supply. Approximately 10% of intracranial DAVFs were associated with aneurysms located in the intraorbital OA. Overall, 70% of lesions were Borden type III, and 50% of patients presented with hemorrhage. In approximately 17% of cases, the source of bleeding was a feeding artery aneurysm. All of the reported intraorbital OA aneurysms associated with DAVFs remained stable during follow-up. DAVF associated aneurysms are fairly rare. Anterior cranial fossa location and direct cortical venous drainage are common among these lesions. The aneurysms are less likely to be located on feeding arteries, and hemorrhagic presentation related to flow-related aneurysm rupture is uncommon.

Multiple high-grade gliomas: epidemiology, management, and outcome. A systematic review and meta-analysis.

Multiple high-grade gliomas (M-HGGs) are well--separated tumors, differentiated as multifocal (MF) and multicentric (MC) by their MRI features. The authors performed a systematic review and meta-analysis of literature examining epidemiology, clinical and radiological characteristics, management, and the overall survival from M-HGGs. According to PRISMA guidelines, a comprehensive review of studies published between January 1990 and January 2017 was carried out. The authors identified studies that examined the prevalence rate, clinical and radiological characteristics, treatment, and overall survival from M-HGGs in patients with HGG. Data were analyzed using a random-effects meta-analysis model. Finally, we systematically reviewed demographic characteristics, lesion location, and surgical and adjuvant treatments. Twenty-three studies were included in this systematic review. The M-HGGs prevalence rate was 19% (95% CI 13-26%) and the hazard ratio of death from M-HGGs in the HGGs population was 1.71 (95% CI 1.49-1.95, p < 0.0001). The MC prevalence rate was 6% (CI 95% 4-10%), whereas MF prevalence rate was 11% (CI 95% 6-20%) (p < 0.0001). There were no statistically significant differences between MF and MC HGGs in gender, lesion location, histological type, and surgical treatment. Survival analysis of MC tumors showed that surgical resection (gross total resection or subtotal resection) is an independent predictor of improved outcome (HR 7.61 for biopsy subgroup, 95% CI 1.94-29.78, p = 0.004). The prevalence of M-HGGs is approximately 20% of HGGs. The clinical relevance of separating M-HGGs in MF and MC tumors remains questionable and its prognostic significance is unclear. When patient status and lesion characteristics make it safe and feasible, cytoreduction should be attempted in patients with M-HGGs because it improves overall survival.

Refinement of the Transoral Approach to Craniovertebral Junction Malformations.

BACKGROUND: The transoral approach provides the most direct surgical corridor for treatment of congenital bony abnormalities that exert irreducible ventral compression of the cervicomedullary junction. In this paper, based on our experience with the transoral approach over the past three decades, we briefly describe the surgical strategies and the operative nuances that allow effective decompression of the craniovertebral junction (CVJ) while minimizing postoperative morbidity. METHODS: The surgical strategy is dictated by the type and severity of the malformation. Fibre-optic nasotracheal intubation obviates the necessity of preoperative tracheostomy, and avoidance of a soft-palate incision significantly reduces oropharyngeal morbidity. When feasible, the atlas-sparing technique minimizes postoperative instability. The transoral transatlas approach is generally required in patients with severe basilar invagination and allows wider exposure of the anterior CVJ at the price of a higher incidence of postoperative instability. CONCLUSION: The transoral approach is extremely effective in providing excellent decompression of the anterior cervicomedullary junction in patients with fixed malformations. Tailoring the approach to the peculiar anatomy of each malformation reduces iatrogenic instability and minimizes postoperative complications.

Realignment of Basilar Invagination by C1-C2 Joint Distraction: A Modified Approach to a Paradigm Shift.

BACKGROUND: Distraction of the C1-C2 joint and maintenance thereof by introduction of spacers into the articular cavity can successfully and durably reduce basilar invagination (BI). Thus, with the adjunct of instrumented fusion and decompression, BI-induced myelopathy can be efficiently treated with a one-stage posterior approach. This intervention is technically challenging, and in this paper we describe a procedural variation to facilitate the approach. METHODS AND RESULTS: Through a description of a case of BI, the main anatomopathological alteration underlying and perpetrating the condition of BI is elucidated. A technique of realignment of BI is then described in which this alteration is specifically targeted and neutralized. The result is a single-stage posterior-only approach with decompression, C1-C2 distraction and introduction of poly(methyl methacrylate) (PMMA) into the joint cavity. Instrumented occipitocervical fusion completes the procedure. CONCLUSION: C1-C2 joint distraction is a technically demanding procedure. By providing a modification of the original technique and a detailed description of the crucial steps necessary to successfully and safely carry it out, we hope to make this excellent procedure more approachable.

Microsurgical anatomy of the sagittal stratum.

BACKGROUND: The sagittal stratum (SS) is a critical neural crossroad traversed by several white matter tracts that connect multiple areas of the ipsilateral hemisphere. Scant information about the anatomical organization of this structure is available in literature. The goal of this study was to provide a detailed anatomical description of the SS and to discuss the functional implications of the findings when a surgical approach through this structure is planned. METHODS: Five formalin-fixed human brains were dissected under the operating microscope by using the fiber dissection technique originally described by Ludwig and Klingler. RESULTS: The SS is a polygonal crossroad of associational fibers situated deep on the lateral surface of the hemisphere, medial to the arcuate/superior longitudinal fascicle complex, and laterally to the tapetal fibers of the atrium. It is organized in three layers: a superficial layer formed by the middle and inferior longitudinal fascicles, a middle layer corresponding to the inferior fronto-occipital fascicle, and a deep layer formed by the optic radiation, intermingled with fibers of the anterior commissure. It originates posteroinferiorly to the inferior limiting sulcus of the insula, contiguous with the fibers of the temporal stem, and ends into the posterior temporo-occipito-parietal cortex. CONCLUSION: The white matter fiber dissection reveals the tridimensional architecture of the SS and the relationship between its fibers. A detailed understanding of the anatomy of the SS is essential to decrease the operative risks when a surgical approach within this area is undertaken.

Patency of the supraclinoid internal carotid artery branches after flow diversion treatment. A meta-analysis.

BACKGROUND AND PURPOSE: Placement of flow-diverters across the ostia of major ICA branches carries a risk of arterial occlusion. We determined the rate of occlusion of the supraclinoid ICA branches and the related symptoms, following coverage with flow-diverters. MATERIALS AND METHODS: A systematic search was performed in PubMed, MEDLINE, and EMBASE. We selected studies reporting treatments with flow-diverters in which the device was placed across the ostium of the OphtA, PcomA, or AchorA. Random-effects meta-analysis was used to pool the following outcomes: rate of arterial occlusion, diminished flow, incidence of related symptoms, factors associated with arterial occlusion. RESULT: Twenty-one studies evaluating 1152 supraclinoid ICA branches were included in the meta-analysis. The incidence of OphtA occlusion and associated symptoms was 5.9% (95 CI% = 3.1-8.6%) (incidence rate = 6% per patient-year), and 0.8% (95% CI = 0.1-1.4%) (incidence rate = 0.8% per patient-year), respectively. Although asymptomatic in all cases, PcomA showed a higher occlusion rate (20.7%, 95% CI = 8.9-32.4%) (incidence rate = 19.5% per patient-year). AchorA was occluded in 1% (95% CI = 0.3-2.4%) of cases, with approximately 1% (95% CI = 0.4-2.3%) of transient neurological symptoms (incidence rate = 0.96% per patient-year). There was a trend toward higher odds of arterial patency among arteries arising from the aneurysm (OR = 2.94, P = 0.06). Demographic factors and multiple stents were not associated with higher risk of arterial impairment. Adequate collateral circulation was reported in 94.5% of patients with arterial occlusion. CONCLUSIONS: During aneurysm treatment, the ostium of the supraclinoid ICA branches can be covered with flow-diverter devices with low rates of neurological symptoms related to arterial occlusion.