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Bin Tang, ShenHao Xie, GuanLin Huang, ZhiGang Wang, Le Yang, XuanYong Yang, Shan Xu, ErMing Zeng and Tao Hong

OBJECTIVE

Transinfundibular craniopharyngioma (TC) is one of the 4 subtypes of suprasellar craniopharyngioma. In this study, the authors analyzed the clinical features of and operative technique for TC.

METHODS

A total of 95 consecutive cases of suprasellar craniopharyngioma that had been resected via the endoscopic expanded endonasal approach were retrospectively reviewed. Patients were divided into 2 groups: 34 in the TC group and 61 in the nontransinfundibular craniopharyngioma (NC) group. Clinical and radiographic features, intraoperative findings, histopathological and genetic findings, and surgical outcomes were analyzed and compared between groups.

RESULTS

Compared with NC, TC was mostly seen in adult patients (97.1%); it was rare in children (2.9%). Clinical presentations tended toward headache, hydrocephalus, and diabetes insipidus. The relatively smaller volume, midline location (consistent with the stalk position), unidentifiable stalk, no shift of the third ventricle, and greater likelihood to involve the third ventricle and cause hydrocephalus were the characteristic features of TC in the preoperative MRI study. According to the degree of vertical extension of the tumor, the 34 TCs could be classified into 3 subtypes: type 1, entity was limited to stalk (n = 2, 5.9%); type 2, tumor extended up to the third ventricle (type 2a) or down to the subdiaphragmatic cavity (type 2b) (n = 23, 67.6%); and type 3, tumor extended in both directions (n = 9, 26.5%). For TC resection, the chiasm–pituitary corridor, lamina terminalis corridor, and pituitary corridor could be used separately or jointly. Most of the TCs originated from the infundibulum–tuber cinereum, grew within and along the long axis of the infundibulum, and the pituitary stalk was not usually preserved in TCs (20.6%), whereas the rate of preservation was higher (80.3%) in NCs. Bilateral hypothalamic injury was found in nearly all TCs if radical resection was performed, whereas the relationship between NCs and hypothalamus was either compression (32.8%) or unilateral invasion (67.2%). Meanwhile, the postoperative endocrine and neuropsychological function outcomes in patients with TC were worse than in patients with NC. The genetic analysis with whole-exome sequencing studies showed no differential mutations of CTNNB1 (β-catenin) and BRAF (V600E) between TC and NC subtypes, but there was a difference between adamantinomatous craniopharyngioma and papillary craniopharyngioma.

CONCLUSIONS

TC is a special subtype of suprasellar craniopharyngioma, which is remarkably different from NC. Identification of this type of tumor preoperatively is essential for the planning of appropriate surgical approach and degree of excision.

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Benjamin Pulli, Christopher J. Stapleton, Brian P. Walcott, Matthew J. Koch, Scott B. Raymond, Thabele M. Leslie-Mazwi, James D. Rabinov and Aman B. Patel

OBJECTIVE

Several grading systems for procedural risk in the endovascular treatment of brain arteriovenous malformations (AVMs) have been proposed, including the Buffalo, Puerto Rico, and AVM embocure scoring systems. The authors sought to validate these systems in an independent patient cohort and compare each system to the established Spetzler-Martin (SM) scale.

METHODS

One hundred four consecutive patients underwent adjunctive endovascular embolization of brain AVMs between 2002 and 2016 with the goal of reducing the surgical or hemorrhagic risk before definitive radiosurgical treatment. Baseline clinical and AVM characteristics, complications, and degree of AVM nidus reduction were obtained retrospectively. Univariate and multivariate comparisons and receiver operating characteristic (ROC) curve analyses were performed.

RESULTS

Ten major (9.6%) and 16 minor (15.4%) complications were encountered in 24 patients (23.1%). An arterial pedicle size < 1 mm (p = 0.001) and a greater number of pedicles (p = 0.039) were predictors of complication occurrence. Only the Buffalo score predicted the complication rate on univariate (p = 0.039) and multivariate (p = 0.001) analyses. ROC curve analysis revealed a greater area under the curve (AUC) of the Buffalo score (0.703) compared to the Puerto Rico score (p = 0.028), AVM embocure score (AVMES; p = 0.010), and SM grade (SMG; p = 0.030). The Buffalo score, Puerto Rico score, and AVMES but not the SMG predicted > 85% nidus reduction. The AUCs for the different scoring systems were not significantly different.

CONCLUSIONS

The major complication rate of 9.6% is within the range of rates reported in the literature and emphasizes that brain AVM embolization is not a low-risk procedure. The Buffalo score but not the Puerto Rico score, AVMES, or SMG predicted the endovascular procedural risk. All three endovascular scores but not the SMG predicted a > 85% nidus reduction rate in this cohort embolized as part of a multimodal AVM treatment.

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Jin W. Tee, Carly S. Rivers, Nader Fallah, Vanessa K. Noonan, Brian K. Kwon, Charles G. Fisher, John T. Street, Tamir Ailon, Nicolas Dea, Scott Paquette and Marcel F. Dvorak

OBJECTIVE

The aim of this study was to use decision tree modeling to identify optimal stratification groups considering both the neurological impairment and spinal column injury and to investigate the change in motor score as an example of a practical application. Inherent heterogeneity in spinal cord injury (SCI) introduces variation in natural recovery, compromising the ability to identify true treatment effects in clinical research. Optimized stratification factors to create homogeneous groups of participants would improve accurate identification of true treatment effects.

METHODS

The analysis cohort consisted of patients with acute traumatic SCI registered in the Vancouver Rick Hansen Spinal Cord Injury Registry (RHSCIR) between 2004 and 2014. Severity of neurological injury (American Spinal Injury Association Impairment Scale [AIS grades A–D]), level of injury (cervical, thoracic), and total motor score (TMS) were assessed using the International Standards for Neurological Classification of Spinal Cord Injury examination; morphological injury to the spinal column assessed using the AOSpine classification (AOSC types A–C, C most severe) and age were also included. Decision trees were used to determine the most homogeneous groupings of participants based on TMS at admission and discharge from in-hospital care.

RESULTS

The analysis cohort included 806 participants; 79.3% were male, and the mean age was 46.7 ± 19.9 years. Distribution of severity of neurological injury at admission was AIS grade A in 40.0% of patients, grade B in 11.3%, grade C in 18.9%, and grade D in 29.9%. The level of injury was cervical in 68.7% of patients and thoracolumbar in 31.3%. An AOSC type A injury was found in 33.1% of patients, type B in 25.6%, and type C in 37.8%. Decision tree analysis identified 6 optimal stratification groups for assessing TMS: 1) AOSC type A or B, cervical injury, and age ≤ 32 years; 2) AOSC type A or B, cervical injury, and age > 32–53 years; 3) AOSC type A or B, cervical injury, and age > 53 years; 4) AOSC type A or B and thoracic injury; 5) AOSC type C and cervical injury; and 6) AOSC type C and thoracic injury.

CONCLUSIONS

Appropriate stratification factors are fundamental to accurately identify treatment effects. Inclusion of AOSC type improves stratification, and use of the 6 stratification groups could minimize confounding effects of variable neurological recovery so that effective treatments can be identified.

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Marcelo Magaldi Ribeiro de Oliveira, Taise Mosso Ramos, Carlos Eduardo Ferrarez, Carla Jorge Machado, Pollyana Helena Vieira Costa, Daniel L. Alvarenga, Carolina K. Soares, Luiza M. Mainart, Pedro Aguilar-Salinas, Sebastião Gusmão, Eric Sauvageau, Ricardo A. Hanel and Giuseppe Lanzino

OBJECTIVE

Surgical performance evaluation was first described with the OSATS (Objective Structured Assessment of Technical Skills) and modified for aneurysm microsurgery simulation with the OSAACS (Objective Structured Assessment of Aneurysm Clipping Skills). These methods rely on the subjective opinions of evaluators, however, and there is a lack of objective evaluation for proficiency in the microsurgical treatment of brain aneurysms. The authors present a new instrument, the Skill Assessment in Microsurgery for Brain Aneurysms (SAMBA) scale, which can be used similarly in a simulation model and in the treatment of unruptured middle cerebral artery (MCA) aneurysms to predict surgical performance; the authors also report on its validation.

METHODS

The SAMBA scale was created by consensus among 5 vascular neurosurgeons from 2 different neurosurgical departments. SAMBA results were analyzed using descriptive statistics, Cronbach’s alpha indexes, and multivariate ANOVA analyses (p < 0.05).

RESULTS

Expert, intermediate-level, and novice surgeons scored, respectively, an average of 33.9, 27.1, and 16.4 points in the real surgery and 33.3, 27.3, and 19.4 points in the simulation. The SAMBA interrater reliability index was 0.995 for the real surgery and 0.996 for the simulated surgery; the intrarater reliability was 0.983 (Cronbach’s alpha). In both the simulation and the real surgery settings, the average scores achieved by members of each group (expert, intermediate level, and novice) were significantly different (p < 0.001). Scores among novice surgeons were more diverse (coefficient of variation = 12.4).

CONCLUSIONS

Predictive validation of the placenta brain aneurysm model has been previously reported, but the SAMBA scale adds an objective scoring system to verify microsurgical ability in this complex operation, stratifying proficiency by points. The SAMBA scale can be used as an interface between learning and practicing, as it can be applied in a safe and controlled environment, such as is provided by a placenta model, with similar results obtained in real surgery, predicting real surgical performance.

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Umeshkumar Athiraman, Diane Aum, Ananth K. Vellimana, Joshua W. Osbun, Rajat Dhar, Rene Tempelhoff and Gregory J. Zipfel

OBJECTIVE

Delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (SAH) is characterized by large-artery vasospasm, distal autoregulatory dysfunction, cortical spreading depression, and microvessel thrombi. Large-artery vasospasm has been identified as an independent predictor of poor outcome in numerous studies. Recently, several animal studies have identified a strong protective role for inhalational anesthetics against secondary brain injury after SAH including DCI—a phenomenon referred to as anesthetic conditioning. The aim of the present study was to assess the potential role of inhalational anesthetics against cerebral vasospasm and DCI in patients suffering from an SAH.

METHODS

After IRB approval, data were collected retrospectively for all SAH patients admitted to the authors’ hospital between January 1, 2010, and December 31, 2013, who received general anesthesia with either inhalational anesthetics only (sevoflurane or desflurane) or combined inhalational (sevoflurane or desflurane) and intravenous (propofol) anesthetics during aneurysm treatment. The primary outcomes were development of angiographic vasospasm and development of DCI during hospitalization. Univariate and logistic regression analyses were performed to identify independent predictors of these endpoints.

RESULTS

The cohort included 157 SAH patients whose mean age was 56 ± 14 (± SD). An inhalational anesthetic–only technique was employed in 119 patients (76%), while a combination of inhalational and intravenous anesthetics was employed in 34 patients (22%). As expected, patients in the inhalational anesthetic–only group were exposed to significantly more inhalational agent than patients in the combination anesthetic group (p < 0.05). Multivariate logistic regression analysis identified inhalational anesthetic–only technique (OR 0.35, 95% CI 0.14–0.89), Hunt and Hess grade (OR 1.51, 95% CI 1.03–2.22), and diabetes (OR 0.19, 95% CI 0.06–0.55) as significant predictors of angiographic vasospasm. In contradistinction, the inhalational anesthetic–only technique had no significant impact on the incidence of DCI or functional outcome at discharge, though greater exposure to desflurane (as measured by end-tidal concentration) was associated with a lower incidence of DCI.

CONCLUSIONS

These data represent the first evidence in humans that inhalational anesthetics may exert a conditioning protective effect against angiographic vasospasm in SAH patients. Future studies will be needed to determine whether optimized inhalational anesthetic paradigms produce definitive protection against angiographic vasospasm; whether they protect against other events leading to secondary brain injury after SAH, including microvascular thrombi, autoregulatory dysfunction, blood-brain barrier breakdown, neuroinflammation, and neuronal cell death; and, if so, whether this protection ultimately improves patient outcome.

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Ilkka Haapala, Markus Karjalainen, Anton Kontunen, Antti Vehkaoja, Kristiina Nordfors, Hannu Haapasalo, Joonas Haapasalo, Niku Oksala and Antti Roine

OBJECTIVE

There is a need for real-time, intraoperative tissue identification technology in neurosurgery. Several solutions are under development for that purpose, but their adaptability for standard clinical use has been hindered by high cost and impracticality issues. The authors tested and preliminarily validated a method for brain tumor identification that is based on the analysis of diathermy smoke using differential mobility spectrometry (DMS).

METHODS

A DMS connected to a special smoke sampling system was used to discriminate brain tumors and control samples ex vivo in samples from 28 patients who had undergone neurosurgical operations. They included meningiomas (WHO grade I), pilocytic astrocytomas (grade I), other low-grade gliomas (grade II), glioblastomas (grade IV), CNS metastases, and hemorrhagic or traumatically damaged brain tissue as control samples. Original samples were cut into 694 smaller specimens in total.

RESULTS

An overall classification accuracy (CA) of 50% (vs 14% by chance) was achieved in 7-class classification. The CA improved significantly (up to 83%) when the samples originally preserved in Tissue-Tek conservation medium were excluded from the analysis. The CA further improved when fewer classes were used. The highest binary classification accuracy, 94%, was obtained in low-grade glioma (grade II) versus control.

CONCLUSIONS

The authors’ results show that surgical smoke from various brain tumors has distinct DMS profiles and the DMS analyzer connected to a special sampling system can differentiate between tumorous and nontumorous tissue and also between different tumor types ex vivo.

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Hardik Sardana, Roshan Sahu and Shweta Kedia

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Nicole Angela Terpolilli, Moritz Ueberschaer, Maximilian Niyazi, Christoph Hintschich, Rupert Egensperger, Alexander Muacevic, Niklas Thon, Jörg-Christian Tonn and Christian Schichor

OBJECTIVE

In meningiomas involving the orbit and optic canal, surgery is the mainstay of therapy. However, radical resection is often limited to avoid functional damage, so multidisciplinary treatment concepts are implemented. Data on the timing and value of early postoperative radiotherapy (PORT) are scarce. This retrospective study analyzes outcomes in patients who underwent targeted resection alone or in combination with early PORT.

METHODS

Patients undergoing resection of orbit-associated WHO grade I meningiomas from January 1999 to December 2013 who presented to the authors’ department at least twice for follow-up were included. Clinical and radiological findings were analyzed retrospectively. Patients were stratified into two cohorts: follow-up with MRI scans at regular intervals, i.e., the watch and wait (W&W) group, and a PORT group receiving PORT within 6 months after surgery in addition to MRI follow-up. Patients in the W&W group were scheduled for treatment when tumor progression was detected by imaging.

RESULTS

One hundred twenty-two patients were included. The mean follow-up was 70 months. The most common symptoms at presentation were visual disturbances; 87.7% of patients received Simpson grade II–III targeted partial resection. Twenty-three patients received PORT, and 99 patients were regularly observed with MRI scans (W&W group). Tumor recurrence/progression occurred significantly later (76.3 vs 40.7 months) and less frequently in the PORT group (13%) than in the W&W group (46.5%). Cases of recurrence were diagnosed an average of 39 months after initial surgery in both groups. PORT patients demonstrated significantly less visual impairment at last follow-up.

CONCLUSIONS

These results indicate that receiving PORT early after targeted partial resection might help to postpone tumor recurrence and the need for additional treatment, while preserving or even improving visual outcome.

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Whitney E. Parker, Elizabeth K. Weidman, J. Levi Chazen, Sumit N. Niogi, Rafael Uribe-Cardenas, Michael G. Kaplitt and Caitlin E. Hoffman

OBJECTIVE

The authors tested the feasibility of magnetic resonance–guided focused ultrasound (MRgFUS) ablation of mesial temporal lobe epilepsy (MTLE) seizure circuits. Up to one-third of patients with mesial temporal sclerosis (MTS) suffer from medically refractory epilepsy requiring surgery. Because current options such as open resection, laser ablation, and Gamma Knife radiosurgery pose potential risks, such as infection, hemorrhage, and ionizing radiation, and because they often produce visual or neuropsychological deficits, the authors developed a noninvasive MRgFUS ablation strategy for mesial temporal disconnection to mitigate these risks.

METHODS

The authors retrospectively reviewed 3-T MRI scans obtained with diffusion tensor imaging (DTI). The study group included 10 patients with essential tremor (ET) who underwent pretreatment CT and MRI prior to MRgFUS, and 2 patients with MTS who underwent MRI. Fiber tracking of the fornix-fimbria pathway and inferior optic radiations was performed, ablation sites mimicking targets of open posterior hippocampal disconnection were modeled, and theoretical MRgFUS surgical plans were devised. Distances between the targets and optic radiations were measured, helmet angulations were prescribed, and the numbers of available MRgFUS array elements were calculated.

RESULTS

Tractograms of fornix-fimbria and optic radiations were generated in all ET and MTS patients successfully. Of the 10 patients with both the CT and MRI data necessary for the analysis, 8 patients had adequate elements available to target the ablation site. A margin (mean 8.5 mm, range 6.5–9.8 mm) of separation was maintained between the target lesion and optic radiations.

CONCLUSIONS

MRgFUS offers a noninvasive option for seizure tract disruption. DTI identifies fornix-fimbria and optic radiations to localize optimal ablation targets and critical surrounding structures, minimizing risk of postoperative visual field deficits. This theoretical modeling study provides the necessary groundwork for future clinical trials to apply this novel neurosurgical technique to patients with refractory MTLE and surgical contraindications, multiple prior surgeries, or other factors favoring noninvasive treatment.