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.