Impact of Travel Distance on Radiation Treatment Modality for Central Nervous System Disease

Background Stereotactic body radiation therapy (SBRT) has emerged as a popular alternative to conventional radiation therapy (RT) over the past 15 years. Unfortunately, the impact of patient distance from radiation treatment centers and utilization of SBRT versus conventional RT has been sparsely investigated. This report represents the first analysis of the impact of patient distance on radiation treatment modality for central nervous system (CNS) disease. Materials and Methods Since the inception of our RADIation oncology And Neuro-Surgery (RADIANS) multidisciplinary clinic at a community hospital in 2016, 27 patients have received either SBRT or conventional RT as their sole radiation treatment modality for CNS disease. Twenty-four (88.9%) presented with metastatic disease. Fisher’s exact test evaluated the relationship between patient residence from treatment (in miles) and radiation treatment modality received. Results Mean patient distance from our RADIANS clinic was 50.6 miles (median = 15.3). Twenty-one patients (77.8%) received SBRT; the remaining six received conventional RT. Mean patient distance from SBRT was 63.6 miles, and mean patient distance for conventional RT was 5.1 miles; this finding was statistically significant (p = 0.0433; 95% confidence interval = 1.9–115.1). Conclusion Our findings indicate that patients with CNS disease who receive SBRT over conventional RT are statistically more likely to reside further from treatment centers. This is similar to findings of national studies comparing proton versus photon treatment for pediatric solid malignancies. The results from our work have implications for neuro-oncology treatment and the development of community hospital-based clinic models similar to RADIANS in the future

RADIANS: A Multidisciplinary Central Nervous System Clinic Model for Radiation Oncology and Neurosurgery Practice

Background Radiation therapy for central nervous system disease commonly involves collaboration between Radiation Oncology and Neurosurgery. We describe our early experience with a multidisciplinary clinic model. Methods In 2016, the novel RADIANS (RADIation oncology And NeuroSurgery) clinic model was initiated at a community hospital. Disease and treatment demographics were collected and analyzed. Patient satisfaction was assessed via a blinded survey questionnaire. Results Forty-two patients have been seen since the inception of RADIANS. The median age was 65; and the median patient distance from RADIANS was 42.7 miles (mean = 62.6; range = 0.7–285). Half of the patients traveled >50 miles to receive care, and >80% were seen for central nervous system metastases. Of the patients receiving radiation, 75% received stereotactic radiosurgery/stereotactic body radiation therapy. The mean overall satisfaction from 0 (not satisfied) to 5 (very satisfied) was 4.8. Conclusions The RADIANS clinic model has proved viable and well-liked by patients in a community setting, with the majority of radiation therapy administered being stereotactic radiosurgery/stereotactic body radiation therapy rather than conventional fractionation

Endoscopic Endonasal Transclival Approach versus Dual Transorbital Port Technique for Clip Application to the Posterior Circulation: A Cadaveric Anatomical and Cerebral Circulation Simulation Study

Purpose  Simulation training offers a useful opportunity to appreciate vascular anatomy and develop the technical expertise required to clip intracranial aneurysms of the posterior circulation. Materials and Methods  In cadavers, a comparison was made between the endoscopic transclival approach (ETA) alone and a combined multiportal approach using the ETA and a transorbital precaruncular approach (TOPA) to evaluate degrees of freedom, angles of visualization, and ergonomics of aneurysm clip application to the posterior circulation depending on basilar apex position relative to the posterior clinoids. Results  ETA alone provided improved access to the posterior circulation when the basilar apex was high riding compared with the posterior clinoids. ETA + TOPA provided a significantly improved functional working area for instruments and visualization of the posterior circulation for a midlevel basilar apex. A single-shaft clip applier provided improved visualization and space for instruments. Proximal and distal vascular control and feasibility of aneurysmal clipping were demonstrated. Conclusions  TOPA is a medial orbital approach to the central skull base; a transorbital neuroendoscopic surgery approach. This anatomical simulation provides surgical teams an alternative to the ETA approach alone to address posterior circulation aneurysms, and a means to preoperatively prepare for intraoperative anatomical and surgical instrumentation challenges

Endoscopic Management of Cavernous Carotid Surgical Complications: Evaluation of a Simulated Perfusion Model

Objective—Endoscopic surgical treatment of pituitary tumors, lateral invading tumors, or aneurysms requires surgeons to operate adjacent to the cavernous sinus. During these endoscopic endonasal procedures, the carotid artery is vulnerable to surgical injury at its genu. The objective of this simulation model was to evaluate trainees regarding management of a potentially lifethreatening vascular injury. Methods—Cadaveric heads were prepared in accordance with the Oregon Health & Science University body donation program. An endoscopic endonasal approach was used, and a perfusion pump with a catheter was placed in the ipsilateral common carotid artery at its origin in the neck. Learners used a muscle graft to establish vascular control and were evaluated over 3 training sessions. Simulation assessment, blood loss during sessions, and performance metric data were collected for learners. Results—Vascular control was obtained at a mean arterial pressure of 65 mm Hg using a muscle graft correctly positioned at the arteriotomy site. Learners improved over the course of training, with senior residents (n = 4) performing better across all simulation categories (situation awareness, decision making, communications and teamwork, and leadership); the largest mean difference was in communication and teamwork. Additionally, learner performance concerning blood loss improved between sessions (t = 3.667, P \u3c 0.01). Conclusions—In this pilot endoscopic endonasal simulation study, we successfully demonstrate a vascular complication perfusion model. Learners were able to gain direct applicable expertise in endoscopic endonasal techniques, instrumentation use, and teamwork required to optimize the technique. Learners gained skills of vascular complication management that transcend this model

Surgical Parameters for Minimally Invasive Trans- Eustachian Tube CSF Leak Repair: A Cadaveric Study and Literature Review

Background Cerebrospinal fluid rhinorrhea from a lateral skull base defect refractory to spontaneous healing and/or conservative management is most commonly managed via open surgery. Approach for repair is dictated by location of the defect, which may require surgical exploration. The final common pathway is the eustachian tube (ET). Endoscopic ET obliteration via endonasal and lateral approaches is under development. Whereas ET anatomy has been studied, surgical landmarks have not been previously described or quantified. We aimed to define surgical parameters of specific utility to endoscopic ET obliteration. Methods A literature review was performed of known ET anatomic parameters. Next, using a combination of endoscopic and open techniques in cadavers, we cannulated the intact ET and dissected its posterior component to define the major curvature position of the ET, defined as the genu, and quantified the relative distances through the ET lumen. The genu was targeted as a major obstacle encountered when cannulating the ET from the nasopharynx. Results Among 10 ETs, we found an average distance of 23 ± 5 mm from the nasopharynx to the ET genu, distance of 24 ± 3 mm from the genu to the anterior aspect of the tympanic membrane and total ET length of 47 ± 4 mm. Conclusions Although membranous and petrous components of the ET are important to its function, the genu may be a more useful surgical landmark. Basic surgical parameters for endoscopic ET obliteration are defined

Measure Twice: Promise of Liquid Biopsy in Pediatric High-Grade Gliomas

Purpose To review and critique the current state of liquid biopsy in pHGG. Materials and Methods Published literature was reviewed for articles related to liquid biopsy in pediatric glioma and adult glioma with a focus on high-grade gliomas. Results This review discusses the current state of liquid biomarkers of pHGG and their potential applications for liquid biopsy development. Conclusions While nascent, the progress toward identifying circulating analytes of pHGG primes the field of neuro-oncoogy for liquid biopsy development

Tumor Treating Fields Utilization in a Glioblastoma Patient with a Preexisting Cardiac Pacemaker: The First Reported Case

Background Tumor-treating fields (TTFs) have become an important, evidence-based modality in the treatment of glioblastoma (GBM). In patients requiring cardiac pacemakers, TTF therapy is complicated by theoretical concerns regarding possible electrical interaction between the devices. Case Description A 57-year-old man with past medical history of sick sinus syndrome requiring cardiac pacemaker implantation suffered an acute neurologic change associated with a left parieto-occipital lesion, which was found to be GBM. After completion of guideline-concordant chemoradiation, he chose to undergo TTF therapy. Because of the absence of cardiac symptoms and the theoretical risk of far-field sensing by the pacemaker of the TTF device (potentially resulting in pacemaker inhibition), the pacemaker was turned off before receiving TTF. Following TTF implementation, the patient responded well; he remains alive more than 25 months following his GBM diagnosis, exceeding the median 20.9-month survival of the recently completed phase III TTF randomized clinical trial for newly diagnosed GBM. Furthermore, he has exhibited neither cardiac morbidity nor adverse scalp reactions to TTF therapy. Conclusions The first reported case of successful TTF administration in a GBM patient with a previously implanted cardiac pacemaker may allay the concerns of neuro-oncologists, cardiologists, radiation oncologists, and all certified TTF prescribers regarding the applicability of TTF in suitable candidates with preexisting cardiac pacemakers. This case indicates that TTF therapy may be efficacious in patients with indwelling magnetic resonance image−conditional cardiac pacemakers turned to the off position and that physical removal of the pacemaker is not necessary before starting TTF

Three-Year Experience of a Multidisciplinary Central Nervous System Clinic Model for Radiation Oncology and Neurosurgery (RADIANS) in a Community Hospital Setting.

Background: As academic centers partner and establish healthcare systems with community hospitals, delivery of subspecialty, multidisciplinary care in community hospital settings remains a challenge. Improving outcomes for central nervous system (CNS) disease is related to integrated care between neurosurgery (NS) and radiation oncology (RadOnc) specialties. Our multidisciplinary community hospital-based clinic, RADIANS, previously reported high patient approval of simultaneous evaluation with NS and RadOnc physicians. Three-year experience is now reported. Methods: Prospectively collected clinical and demographic patient data over three years was done, and surveys administered. Descriptive statistics reported as mean and percentages for patient characteristics, diagnosis, treatment and outcomes. Results: Between August 2016 and August 2019, 101 patients were evaluated. Mean age and distanced traveled was 61.2 years, and 54.9 miles, respectively. Patient Satisfaction Score was 4.79 (0-5 Scale, 5-very satisfied). Most common referral source was medical oncologists. Seventy-two patients had malignant CNS disease (brain mets 28; spine mets 27; both 6; primary brain 9; primary spine 2), 29 had benign CNS disease. Post-evaluation treatment: radiation therapy (RT) only (n=29), neurosurgery (NS) only (n=16), both RT and NS (n=22), and no RT/NS intervention (n=34). Fractionated stereotactic radiosurgery was most common RT delivered; craniotomy with tumor resection was most common NS performed. Treatment outcomes: local control=61/67 (91%); radiation necrosis or radiation-induced myelitis=2/51 (3.9%). Conclusions: The RADIANS multidisciplinary community hospital-based CNS clinic model is first of its kind to be reported, continuing strong patient approval at extended follow-up. Data indicates the model serves as a regional referral center, delivering evidence-based treatment modalities for complex CNS disease in community hospital settings, yielding high rates of local control and low rates of grade 3 or 4 radiation-induced toxicity