Computed Tomography–based Classification of External Jugular Vein Confluence Patterns-- Suitability as a Recipient Vein

Authors: Nakamura S, Yasunaga Y, Nakao J, Araki J, Mori H, Ogino A

Affiliations: Shizuoka Cancer Center and Toho University Omori Medical Center, Japan

Journal: PRS Global Open, 2025.

PMID: 40757385.

Key Takeaways

• The authors identified four external jugular vein (EJV) confluence types (based on CT):

  • SCV — EJV drains to the subclavian vein (47%)

  • Venous angle — EJV drains at the IJV–SCV junction/angle (37%)

  • IJV — EJV drains into the internal jugular vein (11%)

  • Non‑EJV (absent) — no identifiable EJV on CT (5%)

• In 16% (IJV + non‑EJV) of cases, the EJV would be rendered an unsuitable recipient if the IJV is sacrificed.

• Patterns did not differ by side or sex; 46% had matching bilateral patterns.

Background

Recipient‑vein selection drives free‑flap success. Variable EJV terminations can jeopardize outflow when IJV is ligated or resected.

Objective

Define a CT‑based classification of EJV confluence patterns and estimate suitability of the EJV as a recipient vein for microvascular anastomosis.

Classification system

• SCV type: EJV drains to the subclavian vein distal to the venous angle. Interpretation: Generally safe for EJV anastomosis even if IJV is resected.

• Venous angle (VA) type: EJV drains at the junction of IJV and SCV. Interpretation: Usually safe; drainage remains independent of the IJV trunk.

• IJV type: EJV drains into the internal jugular vein proximal to the venous angle. Interpretation: At risk—resection/ligation of IJV can eliminate EJV outflow; plan alternate recipient.

• Non‑EJV type: No identifiable EJV on CT. Interpretation: Treat as unavailable; select a different recipient vein.

Methods

• Design/LOE: Single‑center retrospective observational CT study; Level of Evidence IV.

• Setting/dates: Cancer center; April–November 2022.

• Participants: 50 consecutive patients (100 neck sides); excluded prior head/neck surgery.

• Imaging: Contrast‑enhanced CT (≈2‑mm slices); EJV traced from origin to confluence.

• Endpoints: Primary—distribution of confluence types. Secondary—side/sex differences; bilateral symmetry; clinical suitability.

• Statistics: Descriptive; chi‑square for categorical comparisons (α=0.05).

Results

• Distribution: SCV 47%, venous angle 37%, IJV 11%, non‑EJV 5%.

• Bilateral symmetry: Same pattern both sides in 23/50 patients (46%).

• Side/sex: No significant differences by laterality or sex.

• Clinical context: Two patients required IJV resection; both had SCV‑type EJV.

• Suitability: IJV‑type and non‑EJV together ≈16%—potentially unsuitable for EJV anastomosis if IJV is sacrificed.

Conclusion

Most EJVs terminate in the SCV or venous angle, but ~1 in 6 sides are IJV‑type or lack an EJV and may be unsafe for EJV‑based anastomosis—supporting routine preoperative CT mapping and proactive recipient‑vein planning.

Strengths & Limitations

• Strengths: Practical, CT‑based schema; explicit surgical implications; bilateral assessment in consecutive cohort.

• Limitations: Single‑center retrospective design; small sample; CT may miss very small EJVs; no systematic intraoperative confirmation.

Clinical Relevance

Before head/neck free flaps, check for the presence and branching pattern of the EJV on CT. If IJV‑type or non‑EJV, line up an alternate recipient if there is a chance of ipsilateral IJV sacrifice.