The Impact of Perilesional Heatsink Structures on Ablation Volumes in Laser Interstitial Thermal Therapy for Brain Metastases.

BACKGROUND AND OBJECTIVES: Laser interstitial thermal therapy (LITT) has demonstrated promise in surgical neuro-oncology because of its effectiveness in delivering precise thermal energy to lesions. The extent of ablation (EOA) is a prognostic factor in improving patient outcomes but is often affected by perilesional heatsink structures, which can lead to asymmetric ablations. The purpose of this study was to quantitatively evaluate the impact of various perilesional heatsink structures on the EOA in LITT for brain metastases. METHODS: Twenty-seven procedures for 22 unique patients with brain metastases fit the inclusion criteria. Intracranial heatsink structures were identified: sulci, meninges, cerebrospinal fluid (CSF) spaces, and vasculature. Asymmetric ablation was determined by measuring 3 pairs of orthogonal distances from the proximal, midpoint, and distal locations along the laser catheter to the farthest edge of the ablation zone bilaterally. Distances from the same points on the laser catheter to the nearest heatsink were also recorded. The Heatsink Effect Index was created to serve as a proxy for asymmetric ablation. Pearson correlations, t-tests, and analysis of variance were the statistical analyses performed. RESULTS: From the midpoint of the catheter, the 27 heatsinks were meninges (40.7%), sulci (22.2%), vasculature (22.2%), and CSF spaces (14.8%). Across all points along the catheter track, there was a significant generalized heatsink effect on asymmetric ablations (P < .0001). There was a negative correlation observed between asymmetric ablations and EOA from the midpoint of the laser catheter (r = -0.445, P = .020). Compared with sulci, CSF spaces trended toward a greater effect on asymmetric ablation volumes (P = .069). CONCLUSION: This novel quantitative analysis shows that perilesional heatsinks contribute to asymmetric ablations. CSF spaces trended toward higher degrees of asymmetric ablations. Importantly, neurosurgeons may anticipate asymmetric ablations preoperatively if heatsinks are located within 13.3 mm of the laser probe midpoint. These preliminary results may guide surgical decision-making in LITT for metastatic brain lesions.

The Effect of the Coronavirus Disease 2019 Pandemic on Pituitary Surgery.

OBJECTIVE: As the coronavirus disease 2019 (COVID-19) pandemic spread to the United States in 2020, there was an impetus toward postponing or ceasing nonurgent transsphenoidal pituitary surgeries to prevent the spread of the virus. Some centers encouraged transcranial approaches for patients with declining neurologic function. However, no large-scale data exist evaluating the effects that this situation had on national pituitary practice patterns. METHODS: Pituitary surgeries in the National Inpatient Sample were identified from 2017 to 2020. Surgeries in 2020 were compared with the 3 years previously to determine any differences in demographics, surgical trends/approaches, and perioperative outcomes. RESULTS: In 2020, there was a decline in overall pituitary surgeries (34.2 vs. 36.3%; odds ratio (OR), 0.88; P < 0.001) yet transsphenoidal approaches represented a higher proportion of interventions (69.0 vs. 64.9%; P < 0.001). Neurosurgical complications were higher (51.9 vs. 47.4%; OR, 1.13; P < 0.001) and patients were less likely to be discharged home (86.4 vs. 88.5%; OR, 0.84; P < 0.001). This finding was especially true in April 2020 during the first peak in COVID-19 cases, when transcranial approaches and odds of mortality/complications were highest. CONCLUSIONS: In 2020, transsphenoidal surgery remained the preferred approach for pituitary tumor resection despite initial recommendations against the approach to prevent COVID-19 spread. Pituitary surgeries had a higher risk of periprocedural complications despite accounting for preoperative comorbidities, COVID-19 infection status, and surgical approach, suggesting that an overwhelmed hospital system can negatively influence surgical outcomes in noninfected patients.

Microsurgical versus endovascular treatment of ethmoidal dural arteriovenous fistulas: systematic review and meta-analysis with a single-center case series.

OBJECTIVE: Ethmoidal dural arteriovenous fistulas (DAVFs) are often associated with cortical venous drainage (CVD) and a higher incidence of hemorrhage compared with DAVFs in other locations. They may be treated with open surgical disconnection or with endovascular treatment (EVT). In this systematic review and meta-analysis, the authors compare the outcomes of ethmoidal DAVFs treated with open microsurgery versus EVT and report four additional cases of ethmoidal DAVFs treated with open microsurgery in their institution. METHODS: A literature search of the PubMed and Scopus databases was conducted between December 2021 and May 2022 to identify relevant articles published between 1990 and 2021 using the PRISMA guidelines. References were reviewed and screened by two authors independently, and disagreements were resolved through consensus. Exclusion criteria included non-English-language studies, those with an incorrect study design, those reporting DAVFs in a nonethmoidal location, and studies whose outcomes were not stratified based on DAVF location. Inclusion criteria were any studies reporting on ethmoidal DAVFs treated by either microsurgery or EVT. A risk of bias assessment was performed using the Newcastle-Ottawa Scale. The authors performed a pooled proportional meta-analysis to compare patient outcomes. RESULTS: Twenty studies were included for analysis. Of 224 patients, 142 were treated with surgery, while 103 were treated with EVT. Seventy percent (148/210) of the patients were symptomatic at presentation, with hemorrhage being the most common presentation (48%). CVD was present in 98% of patients and venous ectasia in 61%. The rates of complete DAVF obliteration with surgery and EVT were 89% and 70%, respectively (95% CI -30% to -10%, p < 0.03). Twenty percent (21/103) of endovascularly treated fistulas required subsequent surgery. Procedure-related complications occurred in 10% of the surgical cases, compared with 13% of the EVT cases. The authors' case series included 4 patients with ethmoidal DAVFs treated surgically with complete obliteration, without any postoperative complications. CONCLUSIONS: The complete obliteration rates of ethmoidal DAVF appear to be higher and more definitive with microsurgical intervention than with EVT. While complication rates between the two procedures seem similar, patients treated with EVT may require further interventions for definitive treatment. The limitations of this study include its retrospective nature, the quality of studies included, and the continued evolving technologies of EVT. Future studies should focus on the association between venous drainage pattern and the proclivity toward venous ectasia or rate of hemorrhage at presentation.

State-to-State Variation in Medicaid Reimbursement for Neurosurgical Procedures: Implications for Healthcare Access in Vulnerable Populations.

BACKGROUND AND OBJECTIVES: Medicaid payment for healthcare services traditionally reimburses less than Medicare and commercial insurance. This disparity in reimbursement seems to be an important driver of limited access to care among Medicaid beneficiaries. This study seeks to examine the degree of variation in Medicaid and Medicare reimbursement for the most common neurosurgical current procedural terminology codes and determine its potential impact on provider accessibility. METHODS: In this cross-sectional study, maximum allowed physician reimbursement fees for 20 common neurosurgical codes reported in the literature were obtained from the 2022 Medicare Physician Fee Schedule and individual state Medicaid Fee-for-Service Schedules. The Medicaid-Medicare Index (MMI), which measures Medicaid reimbursement as a fraction of Medicare allowed amounts, was calculated for each procedure across 49 states and the District of Columbia. Lower MMI indicates a greater disparity, or "discount," between Medicaid and Medicare reimbursement. The proportion of providers accepting new Medicaid patients and total Medicaid enrollment were compared across states as a function of MMI. RESULTS: The average national MMI was 0.79, with a range of 0.37 in NY/NJ to 1.43 in NE. Maximum allowed amounts for Medicare reimbursement (coefficient of variation = 0.09) were less variable than those for Medicaid (coefficient of variation = 0.26, P < .01). The largest absolute disparity was observed for intracranial aneurysm clipping in NY, where the maximum Medicaid reimbursement is $3496.52 less than that of Medicare. Higher MMI was associated with a significantly larger proportion of providers accepting new Medicaid patients (R2 = 0.43, P < .01). Moreover, MMI varied inversely with the number of Medicaid beneficiaries (R2 = 0.12, P = .01). CONCLUSION: Medicaid reimbursement varies between states reflecting the disparate methods of fee schedule calculation. Lower reimbursement is associated with more limited provider enrollment, especially in states with a greater number of beneficiaries.