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Background and Purpose: Preoperative compression of middle cerebellar peduncle (MCP) is often observed in vestibular schwannomas. Its re-expansion is expected after tumour resection, however, frequently its thickness remains unchanged or undergoes further atrophy. Similarly, increased MCP FLAIR signal is often observed and thought to be associated with intraoperative MCP injury. This study investigates the dynamics of MCP FLAIR signal changes over time and their implications in long-term MCP atrophy., Materials and Methods: Retrospective analysis of patients operated between 2011 and 2019 was performed. Measurements of FLAIR signals and MCP thickness were performed preoperatively, postoperatively and at follow-up., Results: 28 patients (15 females, mean age 51.94 years) were included. The mean follow-up was 23.98 months. The mean tumour size was 2.99 cm. The MCP FLAIR signal was elevated preoperatively in 10 (35.7%) patients and further increased postoperatively in 22 (78.6%), followed by its decrease at follow up (7 patients, 25%). An immediate postoperative re-expansion of middle cerebellar peduncle was observed in 24 (85.7%) patients. No association between tumour size and preoperative FLAIR was established, however tumour size was negatively associated with the MCP thickness. A significant negative association between a postoperative FLAIR and follow-up thickness ( p  < 0.001) was noted, even if controlling for tumour size and both tumour size and preoperative MCP thickness., Conclusion: In patients with vestibular schwannomas undergoing surgical resection, the middle cerebellar peduncle FLAIR signal seems to associated with long term thickness of MCP, regardless of its initial size, however does not seem to correlate with the clinical outcome.

The goal of this study is to develop a model based on previously used prognostic predictors in traumatic brain injury (TBI) patients with polytrauma, which will facilitate the decision-making of whether to clear these patients for non-cranial surgery. Data of eligible patients was obtained from a trauma database at a Level I trauma and academic tertiary referral center in the United States. The number of days seen by the neurosurgical service prior to clearance, injury severity score (ISS), post-trauma day 0 (PTD 0) of Glasgow Coma Score (GCS), intracranial pressure (ICP) score and computed tomography (CT) score, as well as the changes in GCS, ICP score and CT score between PTD 0 and day of clearance were the variables used in developing the model. The Neurosurgical Clearance Model (NCM) was developed using data from 50 patients included in the study. Patients were cleared by neurosurgeons 1.6 days later than it would appear possible based on a retrospective review of the patients' clinical conditions. A single model equation was developed, the ultimate result of which is a clearance probability value. The best cutoff clearance probability value was found to be 0.584 (or 58.4%) using Receiver Operator Characteristic curve analysis. Our data suggests that neurosurgeons are risk-averse in clearing polytrauma patients for non-cranial surgery. This pilot NCM, if reproduced and validated by other groups and in larger prospective studies, may become a useful tool to assist clinicians in this often-difficult decision-making process., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Objective: Sacroiliac joint (SIJ) arthropathy is an increasingly recognized problem in adult spinal deformity patients undergoing long construct surgery. S2-alar-iliac (S2AI) screw instrumentation is thought to reduce morbidity from pelvic fixation in these patients. The goal of this study is to assess the overall incidence of SIJ arthropathy in patients with long constructs to the pelvis as well as compare SIJ outcomes of partially threaded (PT) versus fully threaded (FT) S2AI screws., Methods: Data of eligible patients were collected from a prospectively maintained database with retrospective review of electronic records at an academic institution between 2016 and 2019., Results: 65 consecutive patients who underwent S2AI screw instrumentation (40 in PT group, 25 in FT group) were enrolled. The rate of postoperative SIJ pain was higher in the PT (52.5 %) compared to FT (32 %) group. There was a significantly shorter time-to-pain development in the PT compared to FT group (11.8 versus 20.1 months, respectively). Of those who developed SIJ pain in the PT group, the pain worsened in 80.9 % versus only 25 % of those in the FT group despite conservative treatment. Cox regression found the PT group more likely to develop SIJ pain at any point during follow-up compared to the FT group (Hazard Ratio = 7.308). SIJ fusion was not detected on imaging of any patient during follow-up., Conclusion: FT S2AI screws are associated with better SIJ outcomes compared to PT screws. However, our data suggest that S2AI screw instrumentation is not sufficient to achieve fusion or prevent development of SIJ pain. Concurrent SIJ fusion may be necessary in patients with long constructs to prevent SIJ arthropathy., (Copyright © 2021. Published by Elsevier B.V.)

Background: Giant and large pituitary adenomas (PA) constitute a specific subset of PAs, with gross total resection (GTR) rates frequently not exceeding 50%. Both an anatomical inaccessibility and an inadequate tumor visualization are thought to play a role. This study analyzes risk factors for postoperative residuals after endoscopic transsphenoidal pituitary surgery for large and giant pituitary adenomas., Methods: A retrospective analysis of patients with giant and large PA operated between 2015 and 2018 was performed., Results: Forty patients (13 females, 27 males) were included in the analysis (30 large and 10 giant PAs). The mean MRI follow-up time was 5.9 ± 6.54 months. Overall, GTR was achieved in 29 patients (72.5%), subtotal resection in 9 (22.5%), and the inconclusive result was in 2 (5%). Unexpected residuals represented 7 (77.7%) of all 9 residual tumors. The most frequent intraoperative factor associated with unexpected residual tumors was improper identification of residual tumor due to obstruction of view in 2 (28.5%) cases and inability to distinguish normal tissue from tumor in the other two (28.5%). Sub-analysis based on tumor size revealed that with large PAs, GTR was achieved in 25 (83.3%), STR in 4 (13.3%), and inconclusive in 1 (3.3%) patient. In patients with giant PAs, GTR was achieved in 4 (40%), STR in 5 (50%), and inconclusive in 1 (10%). Analysis of preoperative factors showed a significant association of residual tumors with larger suprasellar AP distance (p = 0.041), retrosellar extension (p = 0.007), and higher Zurich Score (p = 0.029)., Conclusion: Large and giant PAs are challenging lesions with high subtotal resection rates. Suprasellar AP distance, retrosellar extension, and higher Zurich Score seem to be significant predictors of degree of resection in these tumors. Improving the intraoperative ability to distinguish tumor from a normal tissue might further decrease the number of unexpected residuals.

Background: Factors associated with extent of tumor resection (EOR) and facial nerve outcomes include tumor size, anterior extension of the tumor, patient age, and surgical approach., Objective: To check whether preoperative measurement of the petromeatal (PMA), petroclival (PCA), and petrous-petrous (PPA) angles can help in predicting EOR, facial nerve outcome, and cerebrospinal fluid (CSF) leak occurrence in patients undergoing vestibular schwannoma (VS) surgery via the translabyrinthine approach (TLA)., Methods: A total of 75 patients were included in this retrospective study. Preoperative magnetic resonance imaging constructive interface in steady state and postcontrast T1-weighted sequences through the internal acoustic meatus were used to measure the PMA, PCA, and PPA., Results: There was a statistically significant association between tumor size and EOR; every additional cm in tumor size decreases the odds of gross-total (GTR)/near-total (NTR) resection by 524% (P = .0000355).After controlling for tumor size, the logistic models revealed a significant effect of the angles on EOR. For example, in a patient with a 2-cm VS, every additional degree in PMA, PCA, and PPA increases the odds of GTR/NTR by 2.3% (P = .0000571), 4.05% (P = .0000397), and 0.37% (P = .0000438), respectively.After adjusting for tumor size, sex, and age, the effect of PMA on the occurrence of an immediate postoperative facial nerve deficit and CSF leak indicated a trend towards significance (P = .0581 and P = .0568, respectively)., Conclusion: More obtuse petrous bone angles, namely PMA, PCA, and PPA, are good predictors of GTR or NTR in patients undergoing VS surgery via TLA and may be associated with better facial nerve outcomes and lower CSF leak occurrences., (Copyright © 2020 by the Congress of Neurological Surgeons.)

Background  Transpetrosal approaches have become standard technique for resection of petroclival meningiomas (PCM). The retrosigmoid craniotomy has also been extensively studied as an alternative approach. The need to resect the tentorium at the end of a retrosigmoid approach has been described, but the upfront transtentorial variation of the retrosigmoid craniotomy has never been described nor evaluated in detail as a possible alternative to the standard petrosectomy approaches. Objective  This study was aimed to directly compare the transpetrosal approaches to the retrosigmoid transtentorial approach (RSTTA) in terms of degree of resection, duration of surgery, and estimated blood loss (EBL). Methods  A retrospective case-control study of patients who underwent resection of PCM between January 2014 and December 2018 was performed. Patients in the two surgical approach groups were matched for age and tumor location. The primary measured outcomes were duration of surgery, EBL, extent of resection, length of postoperative hospital stay, and complications. Data analysis was performed using analysis of variance (ANOVA), multivariate analysis of variance (MANOVA), and analysis of covariance (ANCOVA) tests. Results  Thirteen patients had microsurgical resection of PCM at our center between January 2014 and December 2018. Nine patients underwent a transpetrosal approach and four patients underwent RSTTA. The average duration of surgery was shorter in the RSTTA group (425 vs. 525.4 minutes) and had less blood loss (94 vs. 425 mL). Extent of resection was comparable between the groups. Conclusion  The RSTTA appears to be a safe and efficient technique for resecting PCMs and in selected cases a valid alternative to standard petrosectomies approaches., Competing Interests: Conflict of Interest None declared., (Thieme. All rights reserved.)

Background: Trigeminal neuralgia (TN) is characterized by jolts of pain along the distribution of the trigeminal nerve. If patients fail conservative management, microvascular decompression (MVD) is the next step in treatment. MVD is largely done by placing implant pads between the nerve and compressing vessels. We conducted a literature review to assess effectiveness and safety of Teflon™ and Ivalon® sponges for treatment of TN with MVD., Methods: In January 2019, PubMed was searched for manuscripts published in English using permutations of "Microvascular decompression", "Teflon", "Ivalon", "Granuloma", "Polytetrafluoroethylene", "Trigeminal Neuralgia", and "Exploration". Success and relapse rates, causes of relapse, and complication rates were analyzed. We analyzed for relationships with ANCOVA at an alpha threshold of .05., Results: Thirty-six studies representing 4273 patients fit inclusion criteria. Twenty-five dealt with initial MVD, 12 with re-do MVD. Initial MVD initial success rates were 85% in patients receiving Teflon™ (57-100%*) and 91% in patients receiving Ivalon® (79-100%*). Recurrence rates were 12% in Teflon™ patients (0*-30%) and 9.1% in Ivalon® patients (0*-19%). In patients with relapses, implants were the cause in 49% of Teflon™ patients (0*-100%*) and 50% of Ivalon® patients (0*-100%*). Complication rates for patients receiving Teflon™ were 12% (0*-34%) and 19% for patients receiving Ivalon® (0*-40%)., Conclusion: Teflon™ and Ivalon® are two materials used in MVD for TN. It is an effective treatment with long-term symptom relief and recurrence rates of 1-5% each year. Ivalon® has been used less than Teflon™ though is associated with similar success rates and similar complication rates.