Transverse-plane real-time ultrasound-guided cisternal cerebrospinal fluid collection in Beagles: enhanced safety via neurovascular mapping

Objective To develop and evaluate a real-time ultrasound-guided technique for CSF collection from the cisterna magna in dogs, focusing on procedural feasibility, anatomical safety margins, and complication incidence. Methods This prospective experimental study involved 6 healthy adult Beagles housed in a research colony. All dogs were confirmed to be in good general health based on clinical evaluation. The study was conducted at a single veterinary teaching hospital from September 12, 2023, to March 22, 2024. CSF was collected under real-time transverse ultrasound guidance with in-plane needle advancement, and color Doppler was used before insertion and as needed to map adjacent vessels. Results CSF was successfully collected in all 6 dogs without visible blood contamination or neurologic complications. The mean distance from the point of dural penetration to the dorsal surface of the spinal cord was 4.7 mm (95% CI, 4.2 to 5.2 mm), whereas the shortest vertical distance between the dura mater and spinal cord was 1.5 mm (95% CI, 1.4 to 1.6 mm), indicating a favorable anatomical safety margin. All dogs recovered uneventfully from anesthesia, and no neurologic deficits were noted on follow-up examination. Conclusions The real-time ultrasound-guided technique enabled consistent, complication-free cisternal CSF collection in healthy dogs. Anatomical safety margins were clearly delineated sonographically, supporting the feasibility and accuracy of this approach. Clinical Relevance This method enhances the safety and precision of cisternal CSF collection in dogs and may serve as a refined alternative to conventional blind puncture techniques in veterinary neurology.