Common Trajectories for Freehand Frontal Ventriculostomy: A Systematic Review

Background: Freehand ventriculostomy is one of the most commonly performed neurosurgical procedures. While a variety of approaches have been described, frontal via Kocher's point is the most common. Multiple trajectories have been described, but no consensus exists as to the most efficacious. Our objective was to assess the literature regarding trajectories for frontal ventriculostomy and their associated success rates and complications.

Methods: We performed a systematic review of the literature, querying the PubMed/MEDLINE database with the search term "(EVD OR extra-ventricular drain OR ventriculostomy OR external ventricular drain) AND (hand OR freehand OR bedside)" and reported the characteristics and findings of both simulation and clinical studies according to trajectory and catheter position. Final catheter tip position was graded on the Kakarla scale.

Results: A total of 198 abstracts were screened; 40 full papers were assessed. Sixteen were included, 11 of which were clinical studies and 5 of which were simulation studies. Six studies coronally targeted the ipsilateral medial epicanthus (IMC), 4 utilized an orthogonal trajectory (P), and 1 targeted the naison (N). Ideal placement (Kakarla grade 1) was achieved in 954 of 1391 (68.58%) procedures when the IMC was targeted versus 243 of 354 (70.43%) when P was targeted. Potentially harmful (Kakarla grade 3) placement was observed in 142 of 1391 (10.21%) procedures when the IMC was targeted and 20 of 345 (5.80%) when P was targeted. All 5 simulation studies found the IMC target to be inferior.

Conclusions: The IMC is the most prevalent trajectory for frontal ventriculostomy but no target is demonstrably superior. More robust clinical research is required to determine the optimal trajectory.