Stereotactic radiosurgery (SRS) is an effective treatment for patients with multiple brain metastases. Three decades of increasingly powerful scientific studies have shown that SRS improves outcomes and reduces toxicity when it replaces whole-brain radiation therapy (WBRT). Expert opinion surveys of clinicians have reported that the total intracranial tumor volume rather than the number of brain metastases is related to outcomes. As a result, an increasing number of treating and referring physicians have replaced the reflex use of WBRT with SRS, unless the patient has miliary disease or carcinomatous meningitis. In the current era of immunotherapy and targeted therapies with potentially increased systemic disease survival, 10 or more tumors are routinely treated with SRS alone at most academic medical centers. In a single SRS session we routinely treat patients with cumulative tumor volumes of 25 cm³ even if they have ≥10 metastases.

To describe and evaluate outcomes of Gamma Knife radiosurgery (GK) for the treatment of pituitary tumors over the past twenty years, a systematic review and meta-analysis according to PRISMA statement was performed. Articles counting more than 30 patients were included. A weighted random effects models was used to calculate pooled outcome estimates. From 459 abstract reviews, 52 retrospective studies were included. Among them, 18 reported on non-functioning pituitary adenomas (NFPA), 13 on growth hormone (GH)-secreting adenomas, six on adrenocorticotropic hormone (ACTH)-secreting adenomas, four on prolactin hormone (PRL)-secreting adenomas, and 11 on craniopharyngiomas. Overall tumor control and five-year progression free survival (PFS) estimate after one GK procedure for NFPA was 93% (95% CI 89–97%) and 95% (95% CI 91–99%), respectively. In case of secreting pituitary adenomas, overall remission (cure without need for medication) estimates were 45% (95% CI 35–54%) for GH-secreting adenomas, 64% (95% CI 0.52–0.75%) for ACTH-secreting adenomas and 34% (95% CI: 19–48%) for PRL-secreting adenomas. The pooled analysis for overall tumor control and five-year PFS estimate after GK for craniopharyngioma was 74% (95% CI 67–81%) and 70% (95% CI: 64–76%), respectively. This meta-analysis confirms and quantifies safety and effectiveness of GK for pituitary tumors.

Objective: We evaluated factors associated with better outcomes after stereotactic radiosurgery (SRS) when it was performed as the first surgical procedure for medically refractory trigeminal neuralgia. Methods: A total of 121 patients (median age 72 years) with medically refractory pain and no prior surgery underwent Gamma Knife SRS as their initial surgical procedure for trigeminal neuralgia. Using a single 4-mm isocenter, patients received an average maximum dose of 80 Gy, delivered to the trigeminal nerve target defined by intraoperative MRI. The median follow-up was 36 months. Results: Pain relief (Barrow Neurological Institute [BNI] score I–IIIa) was achieved in 107 (88%) patients at a median time of 1 month. Patients who underwent earlier SRS (within 3 years of pain onset) had a shorter interval until pain relief (1 week, p < 0.001), had a longer interval of pain relief off medication (BNI-I, p < 0.001), and had a longer duration of adequate pain control (BNI-I–IIIa, p < 0.001). Median pain-free intervals for patients who underwent SRS at 1, 2, 3, and more than 3 years after trigeminal neuralgia diagnosis were 68, 37, 36, and 10 months, respectively. Patients who responded to SRS within the first 3 weeks after SRS had a longer duration of complete pain relief compared to those with longer response times (p = 0.001). Fifteen patients (12%) reported new sensory dysfunction after SRS. Conclusion: Early SRS as the initial surgical procedure for management of refractory trigeminal neuralgia was associated with faster, better, and longer pain relief when compared to late SRS. Classification of evidence: This study provides Class IV evidence that in patients with medically refractory trigeminal neuralgia, early stereotactic radiosurgery as the initial procedure provides faster, better, and longer pain relief.

Mild traumatic brain injury (mTBI) leads to long-term cognitive sequelae in a significant portion of patients. Disruption of normal neural communication across functional brain networks may explain the deficits in memory and attention observed after mTBI. In this study, we used magnetoencephalography (MEG) to examine functional connectivity during a resting state in a group of mTBI subjects (n = 9) compared with age-matched control subjects (n = 15). We adopted a data-driven, exploratory analysis in source space using phase locking value across different frequency bands. We observed a significant reduction in functional connectivity in band-specific networks in mTBI compared with control subjects. These networks spanned multiple cortical regions involved in the default mode network (DMN). The DMN is thought to subserve memory and attention during periods when an individual is not engaged in a specific task, and its disruption may lead to cognitive deficits after mTBI. We further applied graph theoretical analysis on the functional connectivity matrices. Our data suggest reduced local efficiency in different brain regions in mTBI patients. In conclusion, MEG can be a potential tool to investigate and detect network alterations in patients with mTBI. The value of MEG to reveal potential neurophysiological biomarkers for mTBI patients warrants further exploration.