Chia-Yu Lin

From theory to evidence: long-term evaluation of the mechanism of action and flap integration of distal vascularized lymph node transfers.

BACKGROUND Nonanatomic (distal) placement of vascularized lymph node (VLN) transfers have shown efficacy in the treatment of extremity lymphedema, but the mechanism by which these flaps provide relief of lymphedema remains unclear. Intrinsic lymphovenous connections have been previously shown to exist in the transferred flap. But, the long-term interaction of the VLN flap and surrounding lymphedematous extremity has not been previously investigated. PATIENTS AND METHODS A retrospective review of a prospective maintained database of patients who underwent VLN transfer was evaluated. Patients who underwent distal VLN transfer and had more than 1-year follow-up were identified. Lymphodynamic evaluation was performed using 0.3 to 0.6 mL indocyanine green (ICG) injection at 5 cm proximal to the flap edge on identified patients. Migration direction of dye and latency period was evaluated. RESULTS In total, 20 patients were identified who met inclusion criteria. Average long-term follow-up was 27.3 months. The average circumference reduction of the affected extremity was 40.5%. ICG appearance within the VLN flap was found in all patients occurring on average in 178.3 seconds. In all cases, flow occurred in the distal direction (toward the flap) with proximal placement of dye. Latency period was found to inversely correlate with circumference reduction (p < 0.01). CONCLUSIONS Distal, nonanatomic placement of VLN flaps provide sustained limb circumference reduction in extremity lymphedema patients following a minimum of 1-year postoperatively. Flap integration with the recipient site reliably occurs as witnessed with consistent ICG drainage, and occurs in the gravity-dependent direction. Faster clearance of ICG will result in improved clinical limb circumference reduction.

Preplanning vascularized lymph node transfer with duplex ultrasonography: an evaluation of 3 donor sites.

Background: As experience with vascularized lymph node (VLN) transfer has grown, new VLN sources have become apparent. Descriptive studies have elucidated variable lymph node presence in these donor basins. Yet, no study has evaluated preoperative imaging evaluation between donor sites in patients undergoing VLN transfer. This study was to compare the findings on duplex ultrasonography of the submental, groin, and supraclavicular lymph node basins in patients undergoing VLN transfer. Methods: A review of a prospective database was performed for patients who had undergone preoperative planning for VLN transfer with duplex ultrasonography to provide objective donor-site characteristics. Multiple regression analysis was used to identify factors that correlated with specific flap characteristics. A P value less than 0.05 was considered statistically significant. Results: Sixty-eight patients (28 upper extremities and 40 lower extremities) were identified as undergoing preoperative duplex ultrasonography for VLN transfer. Little variation was seen when evaluating donor sites for laterality in patients. Groin and submental VLN sites had 3.1 and 3.3 lymph nodes, respectively, compared with 0.9 lymph nodes in the supraclavicular donor site (p < 0.01). Increasing age had an inverse relationship with estimated flap volume, whereas higher body mass index correlated with increasing flap thickness. Conclusions: Preoperative imaging with duplex ultrasonography before VLN transfer may allow for accurate identification of specific VLN donor-site characteristics. When considering lymph node–specific characteristics, higher quantity of lymph nodes were found on the groin and submental flap axis compared with the transverse cervical artery axis.

A prospective clinical assessment of anatomic variability of the submental vascularized lymph node flap: Submental Vascularized Lymph Node Flap

The vascularized submental lymph node (VSLN) flap has become a popular choice for the treatment of lymphedema. Despite its favorable characteristics, anatomic variability exists, making the harvest of this flap challenging. Knowledge and characterization of anatomic variability can aid the surgeon in safe and effective flap harvest.

Acoustic Radiation Force Impulse Elastography: Tissue Stiffness Measurement in Limb Lymphedema

Purpose To evaluate the feasibility of cutaneous and subcutaneous limb tissue elasticity measurement in participants with limb lymphedema by using acoustic radiation force impulse (ARFI) elastography. Materials and Methods From July 2015 to June 2017, ARFI elastography was performed in 64 participants with lymphedema (seven men and 57 women; age range, 23-85 years) by using a US system. Tissue stiffness quantification with shear-wave velocity (SWV) was obtained in the cutaneous and subcutaneous limb tissues. Lymphoscintigraphy was the reference standard. Results SWV was significantly higher in limbs with lymphatic obstruction than in unaffected limbs (cutaneous tissue: 2.75 m/sec vs 1.74 m/sec, respectively; subcutaneous tissue: 1.90 m/sec vs 1.35 m/sec, respectively; P < .001). SWV was significantly different among limbs without lymphatic drainage obstruction, with partial obstruction, and with total obstruction (cutaneous tissue: 1.74 m/sec vs 2.75 m/sec vs 2.77 m/sec; subcutaneous tissue: 1.35 m/sec vs 1.90 m/sec vs 1.90 m/sec, respectively; P < .001). By using a cut-off value of 2.10 m/sec and 1.43 m/sec for cutaneous and subcutaneous tissue, respectively, sensitivity was 83.1% (59 of 71) and 80.3% (57 of 71), and specificity was 86.0% (49 of 57) and 70.2% (40 of 57) for manifestation of lymphatic obstruction. The corresponding areas under the receiver operating characteristic curve were 0.91 and 0.83, respectively. Conclusion Acoustic radiation force impulse elastography showed that cutaneous and subcutaneous tissues are stiffer in lymphedematous limbs than in unaffected limbs. Acoustic radiation force impulse elastography is a feasible imaging modality for noninvasive tissue stiffness quantification in limb lymphedema.

Abstract: CT Volumetric Assessment Correlates Strongly with Circumferential Measurement in Patients with Lymphedema and Vascularized Lymph Node Transfers

27/29. Two anastomoses were felt to be insufficient due to venous backflow into the lymphatic vessel. When size match was equivalent, end to end anastomoses were performed. If size mismatch between the chosen vein branch and lymphatic was present, or multiple cut lymphatics were in proximity and had sufficient mobility, an invagination technique was used to maximally restore anterograde lymphatic drainage (5/26). Short term follow-up has revealed no instances of transient or progressive lymphedema.

Abstract: Accurate Prediction of Submental Lymph Nodes Using Magnetic Resonance Imaging and Correlated Clinical Outcome for Lymphedema Surgery

When broken down by anatomical site of the primary, 18 of the 88 patients (20.5%) with lesions on the arm were found to have positive lymph nodes compared to only 4 of the 31 patients (12.9%) with lesions on the forearm. Furthermore, 11 of 58 patients (19.0%) with lesions on the thigh were found to have positive lymph nodes, compared to only 19 of the 135 patients (14.0%) with lesions on the leg. The increase in rate of lymph node positivity when moving from distal to proximal along the limb, approached statistical significance (Z-score 1.4208, p=0.07). The stage of disease was taken into account and on comparison of proximal and distal sites, the stage of disease were comparable (Chi-squared test p=0.55.)

Perfusion-Related Complications and Strategies for Success Following Distal Vascularized Lymph Node Transfers

Introduction: Distal vascularized lymph node (VLN) transfers have shown success in the treatment of symptomatic lymphedema. Although successful in long-term limb circumference reduction, the early post-operative period may be plagued with complications due to flap swelling and interstitial fluid engorgement unique to VLN transfers. These events create a unique set of early complications that may lead to flap loss. The purpose of this study is to evaluate these early complications and review management strategies that have led to successful early outcomes.