In Brazil, shoulder surgeries are traditionally performed under general anesthesia combined with regional blocks. This study aimed to describe the feasibility and safety profile of regional anesthesia with sedation, without general anesthesia, for shoulder surgery. Following approval by the institutional ethics committee, 10 consecutive patients undergoing elective shoulder surgery (arthroscopy, n = 6; arthroplasty, n = 4) received an ultrasound-guided superior trunk block of the brachial plexus combined with an intermediate superficial cervical plexus block using ropivacaine. The primary outcome was the conversion rate to general anesthesia. Secondary outcomes included intraoperative hemodynamic stability, pain scores, post-anesthesia recovery time, length of hospital stay, patient satisfaction (net promoter score, NPS), and complications within 14 days. All blocks were successfully performed (100%). No patient required conversion to general anesthesia (0%). Intraoperative hypotension occurred in 30% of cases and was more frequent in arthroplasty procedures (50%) than in arthroscopy procedures (16.7%). The mean post-anesthesia care unit stay was 51 ± 10 minutes. Seventy percent of patients were discharged on the same day (83.3% of arthroscopy patients and 50% of arthroplasty patients). Only one patient (10%) required rescue opioid (tramadol) within the first 24 hours. Two patients experienced transient hoarseness, which resolved completely within nine hours. No cases of Horner syndrome, persistent neurological symptoms at 24 hours, 7 days, or 14 days, readmissions, or reoperations within 30 days were observed. The NPS was 10 in all patients. Regional anesthesia alone using a superior trunk block combined with a superficial cervical plexus block is feasible and safe for shoulder surgery without the need for conversion to general anesthesia. These preliminary findings support the potential for practice change in Brazil; however, larger studies are needed to confirm these results.

IntroductionTraditional treatment planning for the rotating gamma system (RGS) is a complex and time-consuming process that relies heavily on planner experience. Manual selection of shot size, location, and weight requires extensive trial and error to achieve adequate target coverage (Cov) and dose conformity.MethodsWe developed an automated treatment planning algorithm for RGS using deep reinforcement learning (DRL). Shot placement was modeled as a sequential decision-making process based on target geometry and cumulative dose distribution. A proximal policy optimization (PPO) algorithm was implemented, using target dose Cov and conformal index as reward-related parameters. Thirty clinical brain tumor cases with target volumes ranging from 0.5 to 45 cc were used for evaluation. An additional 15 cases that were not included in the training were used for independent validation.ResultsThe DRL-based algorithm generated clinically acceptable treatment plans across a wide range of tumor sizes. Average dose Cov and selectivity were 92% and 0.79 for tumors <1 cc, 92% and 0.82 for tumors 1-2 cc, 93% and 0.87 for tumors 2-20 cc, and 93% and 0.81 for tumors >20 cc. In the independent test cohort, average Cov and selectivity were 96% and 0.81, respectively. Comparisons with clinical treatment plans created by an experienced planner demonstrated no statistically significant differences in Cov, selectivity, and conformity index (CI, Radiation Therapy Oncology Group (RTOG) criteria), although further improvement in conformity remains desirable. Plan generation time for a single target was less than 10 minutes.ConclusionThe proposed DRL-based automated planning algorithm demonstrates the feasibility of generating RGS treatment plans. The approach achieves plan quality comparable to planner-driven methods while significantly reducing planning time and reliance on user expertise. These results highlight its strong potential to improve efficiency and consistency in stereotactic radiosurgery (SRS) planning.

Stereotactic body radiotherapy (SBRT) is widely practiced in the management of peripheral early-stage non-small cell lung cancer (NSCLC); however, its utility for central tumors is controversial due to the risk of damaging major mediastinal organs. This study evaluates safety and tumor control for centrally located early NSCLC using a moderately hypofractionated SBRT protocol. Between January 2019 and December 2023, 41 patients with central NSCLC who were deemed unfit or declined surgery (T1-T2a N0 M0, tumor diameter ≤ 4 cm) were treated with SBRT (8 Gy × 8 fractions; total dose 64 Gy, BED₁₀ = 115.2 Gy). Central tumors were defined as lesions within 2 cm of the proximal bronchial tree or abutting mediastinal structures. The key outcome was freedom from local progression (FFLP) at three years. Secondary outcomes were regional recurrence-free survival (RRFS), distant recurrence-free survival (DRFS), overall survival (OS), and treatment-related adverse events. The median age was 69.0 years (range: 40-89 years); 65.9% were male. Median tumor diameter was 2.5 cm, and 65.9% measured 2-4 cm. The three-year FFLP was 85.9% (95% CI: 66.1%-94.5%). Three-year OS, RRFS, and DRFS were 68.6% (95% CI: 48.7%-82.1%), 76.8% (95% CI: 56.6%-88.5%), and 83.6% (95% CI: 66.8%-92.3%), respectively. Local failure occurred in four (9.8%), regional failure in nine (22.0%), and distant failure in eight (19.5%) patients. Treatment-related toxicity was minimal (grade ≥ 2 occurrences in 1 patient (2.4%) and no grade ≥ 3 toxicity). A dose of 64 Gy delivered in eight fractions through SBRT exerts good local control and low toxicity for centrally located early-stage NSCLC. This hypofractionated regimen seems to be safe and effective for patients who refuse or are unsuitable for surgery and comparable to results achieved with surgery.

The fragility index (FI) is intended to quantify how many outcome changes would be required to convert a statistically significant two-arm trial result into a nonsignificant one. A reliable statistical metric should produce a result for every valid case it evaluates. This study examined whether a fragility value is always attainable for every statistically significant trial result. FI was analyzed as follows: baseline significance was required (p < 0.05), one-way movement only, and outcome changes were restricted to converting a nonevent to an event in the arm with fewer events, while keeping the arm size fixed. Nonattainability was assessed by determining whether valid 2×2 tables exist for which no finite FI can be obtained under these rules. Evidence is provided through formal counterexamples, complete enumeration of all valid nondegenerate 2 × 2 tables up to total sample size N = 60, and empirical evaluation of published two-arm trials with binary outcomes. Valid baseline-significant 2 × 2 tables exist for which FI is not attainable. A simple counterexample is {3,0,4,11}: baseline two-sided Fisher's exact p = 0.0429, the arm with fewer events is uniquely identified, but that arm has no nonevents available for the required toggle; thus, no legal FI path exists. Enumeration revealed that unattainable cases first appeared at N = 18 and then recurred at every larger sample size through N = 60; by N = 60, a total of 2,390 of 20,774 evaluable baseline-significant tables were unattainable (11.5%). In an empirical dataset of published trials, 2 of 82 baseline-significant evaluable trials (2.4%) were not attainable. The FI is not universally attainable. This is a structural property of the FI algorithm, confirmed by mathematical proof, a complete table enumeration, and published trial data.