Rusheen, Aaron E.

OBJECTIVEThe authors sought to investigate the incidence and predictors of venous thromboembolic events (VTEs) after craniotomy for tumor resection, which are not well established, and the efficacy of and risks associated with VTE chemoprophylaxis, which remains controversial.METHODSThe authors investigated the incidence of VTEs in a consecutive series of patients presenting to the authors’ institution for resection of an intracranial lesion between 2012 and 2017. Information on patient and tumor characteristics was collected and independent predictors of VTEs were determined using stepwise multivariate logistic regression analysis. Review of the literature was performed by searching MEDLINE using the keywords “venous thromboembolism,” “deep venous thrombosis,” “pulmonary embolism,” “craniotomy,” and “brain neoplasms.”RESULTSThere were 1622 patients included for analysis. A small majority of patients were female (52.6%) and the mean age of the cohort was 52.9 years (SD 15.8 years). A majority of intracranial lesions were intraaxial (59.3%). The incidence of VTEs was 3.0% and the rates of deep venous thromboses and pulmonary emboli were 2.3% and 0.9%, respectively. On multivariate analysis, increasing patient age (unit OR 1.02, 95% CI 1.00–1.05; p = 0.018), history of VTE (OR 7.26, 95% CI 3.24–16.27; p < 0.001), presence of motor deficit (OR 2.64, 95% CI 1.43–4.88; p = 0.002), postoperative intracranial hemorrhage (OR 4.35, 95% CI 1.51–12.55; p < 0.001), and prolonged intubation or reintubation (OR 3.27, 95% CI 1.28–8.32; p < 0.001) were independently associated with increased odds of a VTE. There were 192 patients who received VTE chemoprophylaxis (11.8%); the mean postoperative day of chemoprophylaxis initiation was 4.6 (SD 3.8). The incidence of VTEs was higher in patients receiving chemoprophylaxis than in patients not receiving chemoprophylaxis (8.3% vs 2.2%; p < 0.001). There were 30 instances of clinically significant postoperative hemorrhage (1.9%), with only 1 hemorrhage occurring after initiation of VTE chemoprophylaxis (0.1%).CONCLUSIONSThe study results show the incidence and predictors of VTEs after craniotomy for tumor resection in this patient population. The incidence of VTE within this cohort appears low and comparable to that observed in other institutional series, despite the lack of routine prophylactic anticoagulation in the postoperative setting.

Abstract Objective . Stereotactic frame systems are the gold-standard for stereotactic surgeries, such as implantation of deep brain stimulation (DBS) devices for treatment of medically resistant neurologic and psychiatric disorders. However, frame-based systems require that the patient is awake with a stereotactic frame affixed to their head for the duration of the surgical planning and implantation of the DBS electrodes. While frameless systems are increasingly available, a reusable re-attachable frame system provides unique benefits. As such, we created a novel reusable MRI-compatible stereotactic frame system that maintains clinical accuracy through the detachment and reattachment of its stereotactic devices used for MRI-guided neuronavigation. Approach . We designed a reusable arc-centered frame system that includes MRI-compatible anchoring skull screws for detachment and re-attachment of its stereotactic devices. We validated the stability and accuracy of our system through phantom, in vivo mock-human porcine DBS-model and human cadaver testing. Main results . Phantom testing achieved a root mean square error (RMSE) of 0.94 ± 0.23 mm between the ground truth and the frame-targeted coordinates; and achieved an RMSE of 1.11 ± 0.40 mm and 1.33 ± 0.38 mm between the ground truth and the CT- and MRI-targeted coordinates, respectively. In vivo and cadaver testing achieved a combined 3D Euclidean localization error of 1.85 ± 0.36 mm ( p < 0.03) between the pre-operative MRI-guided placement and the post-operative CT-guided confirmation of the DBS electrode. Significance . Our system demonstrated consistent clinical accuracy that is comparable to conventional frame and frameless stereotactic systems. Our frame system is the first to demonstrate accurate relocation of stereotactic frame devices during in vivo MRI-guided DBS surgical procedures. As such, this reusable and re-attachable MRI-compatible system is expected to enable more complex, chronic neuromodulation experiments, and lead to a clinically available re-attachable frame that is expected to decrease patient discomfort and costs of DBS surgery.

Background Cahan's criteria have been utilized since 1948 to establish causality between prior radiation treatment and the development of secondary malignancy. One major criterion specifies that histological and radiographic evidence collected before and after radiation treatment must confirm separate tumor types; however, pretreatment biopsy is rarely obtained prior to radiosurgery for vestibular schwannoma and many other skull base and cranial lesions. Therefore, in these cases Cahan's criteria cannot be validly applied. Objective This article proposes an update to Cahan's criteria using modern molecular genetic analysis for cases lacking baseline histopathology. Methods Mate-pair sequencing and whole exome sequencing of a cerebellopontine angle undifferentiated high-grade pleomorphic sarcoma (UHGPS) that developed after stereotactic radiosurgery of a presumed benign vestibular schwannoma. Results Mate-pair sequencing and whole exome sequencing of the sarcoma revealed complex chromosomal aberrations. Notably, the tumor contained a deletion in the NF2 gene at 22q12 and an in-frame deletion on exon 5 of the remaining copy of NF2. Biallelic events impacting NF2 are atypical for UHGPS but are characteristic for vestibular schwannoma. These findings help support the conclusion that the UHGPS arose from a benign vestibular schwannoma all along. Conclusions Next-generation sequencing can be successfully applied to a radiation-induced sarcoma when both the original and malignant tumors harbor separate signature genetic markers. As our understanding of the genetic profile of various tumors expand, we believe that next-generation sequencing and other genomic tools will play an increasingly important role in establishing causality between radiation and the development of secondary malignancy.