Innovative growth and development of a neurological surgery residency cadaveric spine-simulation training program: a single-institution experience.

OBJECTIVE: Cadaveric and dry 3D model-based simulation training is a valuable educational tool for neurosurgical residents. Such simulation training is an opportunity for residents to hone technical skills and decision-making and enhance their neuroanatomy knowledge. The authors describe the growth and development of the Oregon Health & Science University Department of Neurological Surgery resident-focused, hands-on, spine-simulation surgery courses and provide details of course evaluations, layout, and setup. METHODS: A four-part spine surgical simulation series, including two human cadaveric and two dry 3D model-based courses, was created to provide resident spine procedure training. Residents participated in the spine simulation series (2017-2021) and completed annual course curriculum and anonymous post-course evaluations. Evaluations included both Likert scale items and free-text responses. Responses to Likert scale items were analyzed in Python. Free-text responses were quantified using the Valence Aware Dictionary for Sentiment Reasoner. Descriptive statistics were calculated and plotted using Python's seaborn and matplotlib library modules. RESULTS: The analysis included 129 spine (occipitocervical, thoracolumbar, and spine model fusion I and II) simulation course evaluations. Likert responses demonstrated high average responses for evaluation questions (4.67 ± 0.90 and above). The average compound sentiment value was 0.58 ± 0.28. CONCLUSIONS: This is the first time Likert responses and sentiment analysis have been used to demonstrate how neurosurgical residents positively value a hands-on spine simulation training. Simulation is an essential component of neurosurgical resident education training. The authors encourage other neurosurgical education programs to develop and leverage spine simulation as a teaching tool.

Radiographic predictors of occult intracranial involvement in olfactory neuroblastoma patients.

BACKGROUND: Traditional management of olfactory neuroblastoma (ONB) includes margin-negative resection with removal of cribriform plate, dura, and olfactory bulb, regardless of intracranial disease. This approach may be overtreating certain patients. Our investigation examines risk factors associated with occult intracranial disease to optimize therapeutic outcomes. METHODS: This retrospective, multi-institutional cohort study examined clinical covariates associated with occult intracranial involvement. Patient demographics, staging, Hyam's grade, and pathologic involvement of dura, olfactory bulb/tract, and brain were collected. Diagnostic imaging was reviewed. Positive and negative predictive value (NPV) were estimated along with effect size estimates. Cox hazard regression examined associations with overall survival (OS) and disease-free survival (DFS). RESULTS: A total of 224 subjects with new diagnoses of ONB (2005-2021) were identified. Skull base bone involvement on computed tomography (CT) had the highest NPV for pathologic dura (88.0%), olfactory bulb (88%), and brain involvement (97.3%). Hyam's grade category was significantly associated with dural involvement (φC  = 0.26; 95% confidence interval [CI]: 0.16, 0.42). Subjects without radiologic skull base involvement (n = 66) had pathologic positivity of 12.1%. Within this subgroup, Hyam's grade was clinically significant for dural positivity (φ = 0.34; 95% CI: -0.12, 0.71) with 28.6% involvement in high grade tumors. Neither clinical nor pathologic positivity of intracranial structures were associated with significantly different OS or DFS. CONCLUSIONS: Both CT and magnetic resonance imaging (MRI) had reasonably good NPV for involvement of dura and olfactory bulb. Higher Hyam's grade was associated with dural involvement. Patients with low-grade tumors not involving the skull base may be suitable for avoiding skull base resection; however, further investigation is warranted.

Innovative growth and development of a neurological surgery residency cadaveric skull base simulation training program: A single institution experience.

OBJECTIVE: Neurosurgical cadaveric and simulation training is a valuable opportunity for residents and fellows to develop as neurosurgeons, further neuroanatomy knowledge, and develop decision-making and technical expertise. The authors describe the growth and development of Oregon Health & Science University (OHSU) Department of Neurological Surgery (NSG) resident hands-on simulation skull base course and provide details of course layout and setup. METHODS: A three-part surgical simulation series was created to provide training in cadaveric skull base procedures. Course objectives were outlined for participants. Residents participated in NSG hands-on simulation courses (years 2015-2020) and completed annual course curriculum and anonymous course evaluations, which included free text reviews. Courses were evaluated by Likert scale analysis within Python, and free text was quantified using Valence Aware Dictionary for sEntiment Reasoning (VADER). Descriptive statistics were calculated and plotted using Python's Seaborn and Matplotlib library modules. RESULTS: Analysis included 162 skull base (anterior fossa, middle fossa and lateral, and endoscopic endonasal-based) simulation course evaluations. Resident responses were overwhelmingly positive. Likert responses demonstrated high average responses for each question (4.62 ± 0.56 and above). A positive attitude about simulation courses is supported by an average compound sentiment value of 0.558 ± 0.285. CONCLUSION: This is the first time Likert responses and sentiment analysis have been used to demonstrate how neurosurgical residents view a comprehensive, multi-year hands-on simulation training program. We hope the information presented serves as a guide for other institutions to develop their own residency educational curriculum in cadaveric skull base procedures.

Defining the Clival Recess Surgical Corridor and Clival Classification System for Approach to Sellar Pathology.

BACKGROUND: Sellar masses within the pars intermedius, bordered anteriorly by normal pituitary gland/stalk, and/or with ectatic cavernous carotid anatomy are challenging and high risk when approached through the endonasal standard direct/anterior sellar approach. This approach portends itself to a higher risk of pituitary gland/stalk injury and subtotal resection with the aforementioned anatomic variants. OBJECTIVE: To describe the indirect clival recess corridor approach to sellar lesions. This corridor is a "silent" point of access to lesions in this region endoscopically. While skull base teams may have used this approach to some degree, it has not yet been described in the literature to our knowledge. METHODS: We defined the clival recess surgical corridor with skull base craniometric measurements and use a case example with aberrant anatomy to illustrate the approach. We cross-sectionally reviewed 42 patients with sellar and suprasellar masses. To describe the approach's anatomy, we devised and defined the terms dorsum sella plumb line, anatomic corridor, angle of osseous, and operative corridor. RESULTS: Created novel clival aeration grade informing surgical planning. Classified clival aeration as Grade 1 (100%-75% aeration), Grade 2 (75%-50% aeration), Grade 3 (50%-25% aeration), and Grade 4 (25%-0% aeration). This classification system determines extent of drilling of the clivus required to optimize the clival recess corridor approach and its limitations. CONCLUSION: The clival recess surgical corridor is effective for accessing pituitary lesions within the sella. Consider the indirect approach when a standard direct/anterior sellar approach has high risk for vascular injury and/or endocrinological dysfunction.

A Multidisciplinary Central Nervous System Clinic Model for Radiation Oncology and Neurosurgery (RADIANS): three-year experience with brain and skull base lesions in a community hospital setting.

BACKGROUND: Subspecialty, multidisciplinary care within community hospital settings are limited and remains a challenge. Improving outcomes for central nervous system (CNS) disease rely on integrated subspecialty care between radiation oncology (RadOnc) and neurosurgery (NS). Three-year experience with simultaneous patient evaluation with RadOnc and NS physicians in a community hospital-based CNS clinic model (RADIANS) for brain and skull base lesions (BSBL) are reported. METHODS: Clinical and demographic data were prospectively collected for patients evaluated in RADIANS. Surveys administered and three-year data reviewed. Descriptive statistics reported as mean and percentages for patient characteristics, diagnosis, treatment and outcomes. RESULTS: Sixty-seven patients with confirmed BSBL were evaluated between August 2016 and August 2019. Mean age and distance traveled was 61.0 years and 66.5 miles, respectively. Female (N.=39, 58.2%) and male (N.=28, 41.8%) patients had mean Patient Satisfaction Score of 4.77 (0-5 Scale, where 5 is very satisfied; 26 respondents). Forty-three patients had malignant disease (28 brain mets; six with both brain/spine; nine with primary brain), and 24 had benign disease. Post-evaluation treatment: radiation therapy (RT) only (N.=16), neurosurgery (NS) only (N.=12), both RT and NS (N.=15), and no RT/NS intervention (N.=24). Fractionated stereotactic radiosurgery was most common RT delivered; craniotomy with tumor resection was most common NS performed. Treatment outcomes: local control in 33 of 38 (86.8%); radiation necrosis in one of 31 (3.2%). CONCLUSIONS: The multidisciplinary community hospital-based CNS clinic continues its high patient approval at extended follow-up. Results demonstrate the clinic serves as a regional referral center where patients with BSBL with varying degrees of co-morbidities, systemic disease status, and oncologic staging can be treated with evidence-based treatment modalities yielding high rates of local control and low rates of grade 3 and 4 radiation-induced toxicity, while having access to on-going clinical trials.

Endoscopic Endonasal Eustachian Tube Obliteration as a Treatment for Tension Pneumocephalus After Translabyrinthine Resection of Vestibular Schwannoma.

OBJECTIVE: Cerebrospinal fluid leak and pneumocephalus are rare but potentially devastating complications associated with translabyrinthine resection of cerebellopontine angle masses. Persistent pneumocephalus despite proximal eustachian tube (ET) obliteration is rare. We describe, to our knowledge, the first report of successful management of tension pneumocephalus by endoscopic endonasal ET obliteration using a novel V-loc (Covidien; Medtronic, Minneapolis, MN) suture technique. PATIENTS: A 63-year-old man presented with altered mental status 10 months after translabyrinthine excision of a left cerebellopontine angle vestibular schwannoma measuring 2.8 × 2.9 × 3.3 cm. Computed tomography demonstrated diffuse ventriculomegaly and new pneumocephalus along the right frontal lobe, lateral ventricles, and third ventricle, and air within the left translabyrinthine resection cavity. INTERVENTION: The patient underwent left-sided endoscopic endonasal ET obliteration using 2-0, 9-inch V-loc suture. MAIN OUTCOME MEASURE: Postoperatively, the patient's mental status improved with a decrease in size of the lateral and third ventricles on computed tomography. CONCLUSION: Endoscopic endonasal ET obliteration, a technique previously applied to recalcitrant cerebrospinal fluid leaks, is a safe and reasonable alternative to reentering the original surgical site for patients with pneumocephalus after lateral skull base surgery. Utilizing a V-loc suture for this technique instead of a traditional suture may improve procedural ease and speed.

Geriatric patient outcomes in a multidisciplinary central nervous system community hospital clinic for radiation oncology and neurosurgery (RADIANS).

INTRODUCTION: Management of older adult patients with central nervous system (CNS) cancers requires a patient-centric, multidisciplinary approach. Assessment of neurosurgical and radiation treatment outcomes can assist in establishing guidelines for this patient population. We previously reported on the RADIANS clinic, a novel community hospital-based multidisciplinary clinic (MDC) for CNS cancer care, providing simultaneous radiation oncology and neurosurgery evaluation in a same-day, single-setting clinic. We now provide a focused analysis of our older adult patient population and recommendations for triage and standardization of care. METHODS: Consecutive older adult patients (age ≥ 65) evaluated at the RADIANS clinic for CNS disease were identified and retrospectively reviewed. Observed 30-day neurosurgical outcomes were compared to predicted outcomes determined by the American College of Physicians NSQIP Surgical Risk Calculator. One-sample binomial exact tests were used to evaluate binary outcome measures. A two-sample t-test was used to evaluate the length of hospital stay. Brier Scores were calculated to assess the deviation between predicted probabilities and observed outcomes for binary outcome measures. Overall survival at 90 days was reported. RESULTS: Fifty-six older adult patients with malignant (42/56) and benign (14/56) CNS disease were evaluated. Mean distance traveled for multidisciplinary evaluation at the RADIANS clinic was 43.4 miles. There was no incidence of radiation-induced toxicity. Mean length of hospital stay for RADIANS patients was significantly shorter by about 1.5 to 3.5 days (95% CI). There was no statistically significant difference for other outcome measures, however, Brier Scores demonstrated that NSQIP was not a good predictive tool for any or serious complications, UTI, venous thromboembolism, return to OR, readmission, or death in our cohort. Local tumor control rate and progression-free survival at 90 days were 97.4% and 76.9%, respectively. CONCLUSIONS: This is the first report of CNS disease outcomes in older adult patients evaluated by radiation oncology and neurosurgery at a community hospital-based MDC. We observed minimal adverse radiation outcomes and high tumor control in our cohort. Findings show significantly shorter postoperative hospital stay for patients evaluated and managed at the RADIANS clinic.

Determinants of survival in sinonasal and skull base chondrosarcoma: An analysis of the National Cancer Database.

BACKGROUND: Chondrosarcomas are rare, malignant chondroid tumors that can occur in the sinonasal and skull base regions. Surgery is a mainstay of treatment, but complete resection can be challenging because of the close proximity of critical neurovascular structures. Because of their rarity and relatively indolent nature, optimal treatment regimens are not established. Our objective was to assess determinants of survival for sinonasal and skull base chondrosarcomas utilizing the National Cancer Database (NCDB). METHODS: The NCDB (2004-2017) was queried for cases of sinonasal and skull base chondrosarcoma. Multivariate hazard regression modeling was used to identify significant predictors of 60-month and 120-month overall survival (OS). RESULTS: Seven hundred thirty-six cases met inclusion criteria. OS for all treatment types was 84.7% [SE±0.02] at 60 months and 75.6% [SE±0.02] at 120 months. Surgery with or without adjuvant treatment was found to associate with highest OS at 60 and 120 months. For patients receiving adjuvant radiation during treatment, proton therapy had significantly better OS at 60 months (95.4% [SE±0.03] vs 82.3% [SE±0.03], -2  = 5.27; p = 0.02) and 120 months (85.1% [SE±0.08] vs 72.8% [SE±0.05], -2  = 4.11; p = 0.04) compared with conventional external beam. After adjustment for primary site, multivariate Cox regression modeling (n = 561) identified cofactors significantly associated with variation in mortality risk at 60 and 120 months, including age, Charlson-Deyo total score ≥ 3, insurance provision status, and tumor grade. CONCLUSIONS: Sinonasal and skull base chondrosarcoma are primarily treated with surgery with favorable OS. Adjuvant treatment may be required and proton radiation was associated with improved 60-month and 120-month survival compared with conventional radiation.

Establishing a Multidisciplinary Cavernous Carotid Injury Simulation to Train Neurosurgical, Otolaryngology, and Anesthesia Residents.

Carotid artery injuries are serious complications of endoscopic endonasal surgery. As these occur rarely, simulation training offers an avenue for technique and algorithm development in resident learners. This study develops a realistic cadaveric model for the training of crisis resource management in the setting of cavernous carotid artery injury. An expanded endonasal approach and right cavernous carotid injury is performed on a cadaveric head. The cadaver's right common carotid artery is cannulated and connected to a perfusion pump delivering pressurized simulated blood. A simulation mannequin is incorporated into the model to allow for vital sign feedback. Surgical and anesthesia resident learners are tasked with obtaining vascular control with a muscle patch technique and medical management over the course of 3 clinical scenarios with increasing complexity. Crisis management instructions for an endoscopic endonasal approach to the cavernous carotid artery and blood pressure control were provided to the learners prior to beginning the simulation. An independent reviewer evaluated the learners on communication skills, crisis management algorithms, and implementation of appropriate skill sets. After each scenario, residents were debriefed on how to improve technique based on evaluation scores in areas of situational awareness, decision-making, communications and teamwork, and leadership. After the simulation, learners provided feedback on the simulation and this data was used to improve future simulations. The benefit of this cadaveric model is ease of set-up, cost-effectiveness, and reproducibility.

Development of a Cadaveric Multiport Model of Posterior Circulation Aneurysm Clipping for Neurosurgery and Otolaryngology Residents.

Posterior circulation aneurysms are difficult to treat with the current methods of coiling and clipping. To address limitations in training, we developed a cadaveric model to train learners on endoscopic clipping of posterior circulation aneurysms. An endoscopic transclival approach (ETA) and a transorbital precaruncular approach (TOPA) to successfully access and clip aneurysms of the posterior circulation are described. The model has flexibility in that a colored silicone compound can be injected into the cadaveric vessels for the purpose of training learners on vascular anatomy. The other option is that the model could be connected to a vascular perfusion pump allowing real-time appreciation of a pulsatile or ruptured aneurysm. This cadaveric model is the first of its kind for training of endoscopic clipping of posterior circulation aneurysms. Learners will develop proficiency in endoscopic skills, appropriate dissection, and appreciation for relative anatomy while developing an algorithm that can be employed in a real operative arena. Going forward, various clinical scenarios can be developed to enhance the realism, allow learners from different specialties to work together, and emphasize the importance of teamwork and effective communication.

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.

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.

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.

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.

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.

Radiation recall myelitis following paclitaxel chemotherapy: The first reported case.

INTRODUCTION: Stereotactic body radiotherapy (SBRT) of the spine has become an increasingly utilized modality in the United States, most commonly for metastatic disease (McClelland et al., 2017). Spinal SBRT in patients with spinal instrumentation has been sparsely examined. We report a patient who developed myelitis following spinal SBRT to a region with existing hardware. METHODS: A 55-year-old woman with Stage IV breast cancer developed a T4 vertebral body metastasis and underwent tumor debulking with posteriorly instrumented T3-T5 fusion. Postoperatively she proceeded with SBRT to the T3-T5 vertebral bodies, receiving 30 Gy in 6 Gy/fraction. Seven months later, she required paclitaxel chemotherapy (80 mg/m2 per cycle) for new liver metastases. RESULTS: Eight months following spine SBRT, four weeks after having started chemotherapy she developed intractable back pain and right lower extremity numbness which improved upon receiving steroids for weekly chemotherapy; the numbness subsequently spread to her left leg. Thoracic spine MRI revealed a 1.7 cm ovoid focus of T4-T5 spinal cord enhancement with extensive surrounding cord edema extending superiorly to C6-C7, consistent with radiation myelitis. Hyperbaric oxygen moderately improved her symptoms; fortunately, she never developed motor symptomatology or bowel/bladder dysfunction. Thorough re-evaluation of the original thoracic spine SBRT plan revealed no deviations from the standard of care, nor did re-planning with alternate treatment planning software demonstrate any significant difference in maximum cord dosage than the original plan. CONCLUSIONS: The timing of symptomatology related to chemotherapy administration is consistent with radiation recall myelitis, which has yet to be reported following SBRT. Given the potentially disastrous consequences of myelitis, patients with metastatic disease previously treated with spine SBRT may be susceptible to developing myelitis if treated with paclitaxel chemotherapy.

Long-term stroke risk of single-fraction photon-based stereotactic radiosurgery for meningioma.

OBJECTIVES: A recent randomized study of fractionated radiation therapy (RT) examining 44 subtotally resected/recurrent benign meningioma patients revealed that at median follow-up of 17.1 years, the risk of stroke following proton-photon RT was 20.5%; the average stroke developed 5.6 years following RT completion (Sanford et al., 2017). This stroke risk is up to 10 times higher than the 2-6% rate expected for the general population of ages 40-79 (Mozaffarian et al., 2015). The stroke rate following single-fraction stereotactic radiosurgery (SRS) has not been previously studied in meningioma patients. PATIENTS AND METHODS: A PubMed database search for relevant articles examining SRS for meningioma with minimum mean/median follow-up of six years was undertaken. Stroke rate was assessed either from direct description in manuscripts, or from extrapolating post-SRS complications from reported clinical examinations (i.e. hemiparesis/weakness, pituitary dysfunction following treatment of cavernous sinus lesions). Results were then culled to determine an overall stroke rate. RESULTS: Fourteen studies met inclusion criteria; 1431 patients received photon-based SRS for meningioma with a sufficient long-term follow-up. Median/mean follow-up ranged from 75 to 144 months. Operative resection prior to SRS occurred in 769/1377 patients (55.8%) for whom surgical history was reported. Twenty-four patients suffered a stroke following SRS, yielding a rate of 1.7%. CONCLUSIONS: The long-term stroke rate following single-fraction photon-based SRS for benign meningioma was 1.7%, more than twelve times lower than for fractionated proton-photon RT and comparable to that expected for the general population. The majority of patients underwent resection prior to SRS. These findings indicate that for patients with benign meningioma desiring to avoid the high stroke risk of fractionated proton-photon RT, SRS has a comparable stroke risk profile to observation. Such findings are pertinent for radiation oncology, neuro-oncology, and neurosurgery management of these patients.

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.

Integrated Otolaryngology and Anesthesia Simulation Model for Crisis Management of Cavernous Carotid Artery Injury.

Simulation training is emerging as a cost-effective way to train residents on the skill sets necessary to excel as fully functioning physicians. Until recently, the simulated resident training environments have primarily focused on handling a medical crisis with learners from the same specialty. A dual otolaryngology and anesthesiology simulation was established to improve teamwork and communication skills between specialties. One otolaryngology resident was paired with one anesthesia resident per trial in our study. The multispecialty team addressed three clinical simulation scenarios to manage a cavernous carotid artery-bleeding crisis with an endoscopic endonasal approach. An independent reviewer evaluated each individual based on situation awareness, decision-making, communications and teamwork, as well as leadership. Residents improved on blood loss, pre and post anatomical exam scores, and communication measures through the course of the scenarios. Residents from both specialties rated the simulation highly and wanted further simulation training in the future. Multidisciplinary simulation training is a novel approach for improving communication skills between specialties prior to entering the wards, clinic, or operative arena. The lessons learned from this multidisciplinary simulation transcend the individual experience by allowing trainees to develop algorithms for crisis management and to improve on aspects of teamwork, leadership, and communication skills that can be applied throughout their careers.

Minimally invasive endoscopic repair of refractory lateral skull base cerebrospinal fluid rhinorrhea: case report and review of the literature.

Cerebrospinal fluid (CSF) leaks occur in approximately 10% of patients undergoing a translabyrinthine, retrosigmoid, or middle fossa approach for vestibular schwannoma resection. Cerebrospinal fluid rhinorrhea also results from trauma, neoplasms, and congenital defects. A high degree of difficulty in repair sometimes requires repetitive microsurgical revisions-a rate of 10% of cases is often cited. This can not only lead to morbidity but is also costly and burdensome to the health care system. In this case-based theoretical analysis, the authors summarize the literature regarding endoscopic endonasal techniques to obliterate the eustachian tube (ET) as well as compare endoscopic endonasal versus open approaches for repair. Given the results of their analysis, they recommend endoscopic endonasal ET obliteration (EEETO) as a first- or second-line technique for the repair of CSF rhinorrhea from a lateral skull base source refractory to spontaneous healing and CSF diversion. They present a case in which EEETO resolved refractory CSF rhinorrhea over a 10-month follow-up after CSF diversions, wound reexploration, revised packing of the ET via a lateral microscopic translabyrinthine approach, and the use of a vascularized flap had failed. They further summarize the literature regarding studies that describe various iterations of EEETO. By its minimally invasive nature, EEETO imposes less morbidity as well as less risk to the patient. It can be readily implemented into algorithms once CSF diversion (for example, lumbar drain) has failed, prior to considering open surgery for repair. Additional studies are warranted to further demonstrate the outcome and cost-saving benefits of EEETO as the data until now have been largely empirical yet very hopeful. The summaries and technical notes described in this paper may serve as a resource for those skull base teams faced with similar challenging and otherwise refractory CSF leaks from a lateral skull base source.