Practical Lymphatic Ultrasound for Supermicrosurgical Lymphaticovenous Anastomosis: Preoperative Lymphatic Mapping Using Conventional High-Frequency Ultrasound

Malagón & Yamamoto, Ann Plast Surg, 2025; PMID 40400056

Key takeaways

• High‑frequency ultrasound (HFUS, 18 MHz) identified lymph vessels in 99.7 % of 349 incisions across 97 limbs.

• Mean lymphatic / venous diameters: 0.65 mm vs  0.81 mm.

• Limb volume index fell 281.2 → 267.6 (LEL, P = 0.002) and LeQOLiS improved 48.3 → 21.9 (P < 0.001).

• Median incision length 1.97 cm; LVA took 21.7 min on average.

• Standardized eight‑step HFUS protocol streamlines pre‑op mapping for supermicrosurgical LVA.

Background 

Lymphovenous anastomosis efficacy hinges on locating functional collectors and reflux‑free veins. Ultrasound offers a radiation‑free, bedside alternative to ICG or MR lymphangiography but lacks standardization.

Objective 

Describe a reproducible HFUS mapping technique and evaluate its reliability, accuracy, and clinical impact in secondary lower‑limb lymphedema.

Methods

• Design: Technical description plus retrospective analysis (Level III).

• Setting: Two tertiary centers, Barcelona & Tokyo.

• Patients: 61 patients (all women), 97 lower limbs, secondary lymphedema post‑gynecologic cancer; mean age 56.7 y; BMI 23.5.

• Intervention: Pre‑op HFUS (18 MHz linear probe) mapping the day before surgery; markings for lymph vessels & superficial veins.

  Eight‑step HFUS protocol: 

  • Transducer – choose ≥15–18 MHz linear probe.

  • Preset – select “superficial abdomen/vessels” setting.

  • Mode, depth & gain – use B‑mode; depth ≈2 cm; gain ~66.

  • Anatomical layers – identify dermis, subcutaneous tissue, superficial fascia.

  • Focus – set focal zone just below superficial fascia.

  • Lymph vessel – trace hypoechoic channel with halo; confirm no Doppler signal.

  • Vein – locate nearby compressible superficial vein, similar or larger diameter.

  • Marking – mark lymph (green) and vein (blue) paths; plan incision perpendicular.

• Surgical data: incision number/length, LVA count, time per LVA, vessel diameters, detection rate.

• Outcomes:

  • LEL index – limb‑volume index derived from circumferential measurements (lower score = less edema); recorded pre‑ and post‑LVA.

  • LeQOLiS – Lower‑Extremity Lymphedema Quality‑of‑Life Score (0–100, higher = worse QoL); self‑reported pre‑/post‑op.

• Statistics: Paired t‑test; significance p < 0.05.

Results

• Detection: ≥1 lymph vessel found in 99.7 % of incisions.

• Workload: 3.7 ± 1.9 LVA/limb; 21.7 min per anastomosis.

• Incisions: 1.97 cm (1.2–3.8).

• Volumes/QoL: LEL −13.6 points; LeQOLiS −26.4 points (both significant).

• No major complications.

Conclusion An eight‑step HFUS protocol enables reliable pre‑operative mapping, allows small incisions and short operative times, and is associated with meaningful limb‑volume reduction and QoL gains.

Strengths & limitations 

• High vessel detection and objective postoperative improvements.

• Detailed practical protocol enhances reproducibility.

• Operator‑dependent; single sonographer/device.

• No imaging comparator or randomized control.

• Only secondary lower‑limb cases—generalizability limited.

Future directions Assess learning curves across centers, compare HFUS with UHFUS/ICG‑L in RCTs, and extend to primary and upper‑limb lymphedema.

Clinical relevance Plastic surgeons can integrate HFUS mapping into outpatient workflow to target >0.6 mm lymph vessels and adjacent low‑pressure veins, shortening operations, improving identification of functional lymphatics, and improving outcomes.