Off-Hours Neurosurgical Workload at a Chilean Public Referral Center: Urgent Caseload, Scheduled After-Hours Lists, and Temporal Patterns

Background: Off-hours surgery has been associated with adverse outcomes and workforce strain, but systematic data from Latin American public neurosurgical services are scarce. We aimed to quantify the proportion, composition, and five-year trajectory of off-hours neurosurgical activity in a Chilean public tertiary centre and to identify scheduling patterns relevant to workforce planning. Methods: In this retrospective cohort study, we included all consecutive neurosurgical procedures recorded in the prospective registry of Hospital Las Higueras (Talcahuano, Chile), the sole neurosurgical emergency referral centre for approximately 1·2 million people, between Jan 1, 2021, and Oct 30, 2025. Procedures were classified as elective (weekdays 08:00–17:00) or off-hours (weekdays 17:00–08:00, weekends, and holidays). The main outcome was the annual off-hours proportion (Wilson 95% CIs); monthly volumes were examined with seasonal-trend decomposition via loess (STL). The ethics committee waived individual consent. Findings: Of 1395 procedures, 638 (45·7%; 95% CI 43·1–48·4) were off-hours: 400 (28·7%) on weekday evenings or nights and 238 (17·1%) on weekends or holidays. The annual off-hours proportion rose from 23·6% (26 of 110) in 2021 to 56·5% (204 of 361; 51·4–61·5) in 2024 (+32·9 percentage points). Off-hours rates were highest for urgent high-complexity procedures (eg, epidural haematoma evacuation, 84·9% [72·9–92·1]). Facet joint block, a low-complexity elective procedure, had a 68·6% (59·9–76·2) off-hours rate concentrated on weekday evenings, consistent with displacement of elective work by daytime capacity deficit rather than clinical urgency. STL showed a reproducible October–December seasonal peak across 2022–24. Interpretation: Off-hours neurosurgical activity more than doubled over five years, driven by growth of urgent caseload and by displacement of elective procedures into on-call time; both are modifiable. These data provide a reference point for Latin American public neurosurgical services and support seasonally informed staffing. Multicentre, outcome-linked studies are needed to establish generalisability and patient-level consequences.