Free forearm flaps for head and neck reconstruction: fewer revisions and flap failures with two venous anastomoses – a 25-year prospective study

Authors: Kuijpers CJ, Van Cann EM, Dieleman FJ, Bergsma JE, van Es RJJ, Rosenberg AJWP

Affiliation: University Medical Center Utrecht, the Netherlands

Journal: International Journal of Oral and Maxillofacial Surgery, January 2026

PMID: 41130859

Key takeaways

• Two venous anastomoses were associated with fewer takebacks and flap failures in free forearm flap head and neck reconstruction.

• Primary RFFF

  • Revision: 8.8% with one vein vs 2.9% with two veins; P = 0.045.

  • Failure: 8.8% with one vein vs 2.1% with two veins; P = 0.018.

• Full cohort (Ulnar and radial forearm flaps)

  • Revision: 8.3% with one vein vs 2.8% with two veins; P = 0.031.

  • Failure: 6.7% with one vein vs 2.0% with two veins; P = 0.033.

• A single venous anastomosis independently predicted vascular revision (adjusted OR 3.16; P = 0.039) and flap failure (adjusted OR 4.50; P = 0.015).

Background

Free forearm flaps are workhorse flaps for head and neck reconstruction. Vascular compromise remains uncommon but consequential, and the value of a second venous anastomosis remains debated.

Objective

Determine whether two venous anastomoses reduce surgical vascular revision and flap failure compared with one venous anastomosis in free forearm flap head and neck reconstruction.

Methods

• Design: Prospective single-center cohort, 1998–2023; Level III evidence.

• Population: 364 patients, 368 free forearm flaps.

  • 314 radial free forearm flaps (RFFF); 54 ulnar free forearm flaps (UFFF).

  • 359/368 flaps (97.6%) were primary reconstructions.

• Primary analysis: 306 primary RFFF.

  • One vein: 68.

  • Two veins: 238.

• Full cohort analysis: All RFFF and UFFF, primary and secondary reconstructions (368).

  • One vein: 120.

  • Two veins: 248.

• Baseline balance: Primary RFFF groups were similar for sex, age, ASA class, T-stage, prior radiotherapy, and sampled smoking status. In the full cohort, one-vein patients were slightly older and UFFF were disproportionately in the one-vein group.

• Technique: Arterial anastomoses were end-to-end. Venous anastomoses were end-to-end or end-to-side; couplers were introduced in 2019 at surgeon discretion. One surgeon routinely completed a single venous anastomosis, while the other three routinely completed two.

• Venous drainage, full cohort:

  • One-vein flaps used the deep system in 92.5%.

  • Two-vein flaps used both superficial and deep systems in 89.3%.

  • Internal jugular vein was the recipient vein in 93.2% of venous anastomoses.

• Outcomes: Surgical vascular revision and partial or total flap failure within 4 weeks.

• Statistics: Fisher exact testing for group comparisons; multivariable logistic regression in the full cohort adjusted for age and flap type.

Results

Primary RFFF subgroup

• Vascular revision: 6/68 (8.8%) with one vein vs 7/238 (2.9%) with two veins; P = 0.045; RR 3.00, 95% CI 1.04–8.63.

• Flap failure: 6/68 (8.8%) with one vein vs 5/238 (2.1%) with two veins; P = 0.018; RR 4.20, 95% CI 1.32–13.34.

• Overall primary RFFF failure: 11/306 (3.6%): 9 total and 2 partial failures.

• Revision etiology: 7 venous, 3 arterial, 3 combined arterial/venous.

• Revision timing: 10/13 revisions occurred on postoperative day 1.

• Salvage after revision: 10/13 revised flaps (76.9%) were salvaged.

Full cohort

• Vascular revision: 10/120 (8.3%) with one vein vs 7/248 (2.8%) with two veins; P = 0.031; RR 2.95, 95% CI 1.15–7.56.

• Flap failure: 8/120 (6.7%) with one vein vs 5/248 (2.0%) with two veins; P = 0.033; RR 3.31, 95% CI 1.11–9.89.

• Overall flap survival: 355/368 (96.5%).

• Overall flap failure: 13/368 (3.5%): 11 total and 2 partial failures.

• Revision etiology: 10 venous, 4 arterial, 3 combined arterial/venous.

• Revision timing: 12/17 revisions occurred on postoperative day 1.

• Salvage after revision: 13/17 revised flaps (76.5%) were salvaged.

• UFFF: 2/47 one-vein UFFF failed; 0/7 two-vein UFFF failed.

Multivariable analysis, full cohort

• Surgical vascular revision: one vs two veins, adjusted OR 3.16; 95% CI 1.06–9.44; P = 0.039.

• Flap failure: one vs two veins, adjusted OR 4.50; 95% CI 1.34–15.05; P = 0.015.

• Age and flap type were not significantly associated with either outcome.

Conclusion

In this 25-year prospective cohort, two venous anastomoses were associated with lower vascular revision and flap failure rates than one venous anastomosis. The authors conclude that a second venous anastomosis should be considered to reduce flap failure risk, while acknowledging that confirmation requires randomized trials or forearm flap-specific meta-analysis.

Strengths

• Consecutive prospective cohort with clear early vascular endpoints.

• 25-year institutional experience.

• Separate, cleaner analysis of primary RFFF.

• Same directional signal in both the primary RFFF subgroup and full cohort.

Limitations

• Nonrandomized allocation; number of veins was influenced by surgeon preference.

• Single-center, four-surgeon series over a long period with evolving technique and perioperative practice.

• Smoking was not prospectively documented and was only retrospectively sampled.

• Low event rates yield wide confidence intervals and limited subgroup power.

• Cannot determine whether benefit comes from simply adding a second vein or specifically from dual-system drainage.

• Venae comitantes size was not reported.

Clinical relevance

For RFFF or UFFF head and neck reconstruction, this study supports a low threshold for two venous anastomoses when anatomy and recipient vessels allow. The absolute flap failure reduction was clinically meaningful: 8.8% to 2.1% in primary RFFF and 6.7% to 2.0% in the full cohort.

Editorial notes

This study asks a long-debated question: does adding a second venous anastomosis reduce takeback and flap loss in head and neck reconstruction? In this cohort, one-vein flaps had consistently higher revision and failure rates in both the primary RFFF subgroup and the full cohort.

The main caveat is confounding. Anastomosis number was not randomized and may reflect surgeon preference, era, flap type, recipient-vessel quality, ischemia time, or defect complexity. Failures were also not stratified by surgeon or early versus late study period.

A key missing detail is venae comitantes caliber. A prior study (Yu 2011) suggested that deep-system drainage is reliable when the venae comitantes are at least 1 mm at the wrist incision, while smaller venae comitantes should prompt use of the superficial system. Kuijpers reports whether the deep and/or superficial systems were used, but not VC size. That distinction matters: the worse outcomes in one-vein flaps may reflect inadequate deep-system caliber, lack of second-system redundancy, or both.

Because most two-vein flaps used both superficial and deep systems, this paper is best read as support for dual outflow when feasible, not definitive proof that any two equivalent veins are superior to one.