Improvement of the efficacy of vascularized lymph node transfer for lower-extremity lymphedema via a prefabricated lympho-venous shunt through lymphaticovenular anastomosis between the efferent lymphatic vessel and small vein in the elevated vascularized lymph node

Surgical options for lymphedema after gynecological cancer treatment: current trends and advances

Lower leg lymphedema is an important complication after gynecological treatment that can severely affect the quality of life of long-term survivors of these malignancies. As a chronic and progressive disease, affected patients will require life-long therapy centered on compression. Although conventional compressive treatments can be effective, they are extremely burdensome and time-consuming for most patients and adherence is challenging. With advances in the field of reconstructive microsurgery, new procedures have been developed in the past decades to help these patients in their continuous care and have been offered at many oncological centers around the world as a first line of treatment. We performed a PubMed search using the Mesh terms 'Lymphedema/surgery' and 'Lower extremity' yielding a total of 508 articles. Of these, 35 articles were included for analysis. Articles that failed to provide a comprehensive analysis of outcomes following surgical treatment, studies examining treatment for upper limb lymphedema, primary lymphedema, or lower extremity lymphedema resulting from non-gynecologic etiologies, and studies that failed to have a minimum of 6 months follow-up were excluded. A comprehensive review of these 35 articles including over 1200 patients demonstrated large variability on the outcomes reported; however, an overall benefit from these procedures was found. Surgical options including lymphovenous anastomosis, vascularized lymph node transfers, and excisional procedures can be performed in patients with lower leg lymphedema, depending on staging and findings in indocyanine green lymphography. Surgical treatment of lymphedema is an effective option that can improve symptoms and quality of life of patients suffering from lymphedema following gynecologic cancers.

Sentinel node restoration by vascularized lymph node transfer in mice

BACKGROUND

Recent reports have indicated that vascularized lymph node transfer (VLNT) may improve the impaired immunity in lymphedema but there has been no report concerning anti-cancer immunity. In the early tumor immune response, dendritic cells (DCs) participate in tumor recognition and antigen presentation in local lymphatics. Here, we investigated the impact of VLNT on DC dynamics against cancer in mouse models.

METHODS

Forty-seven 8-week-old C57BL/6 N male mice were divided into three surgical groups: a VLNT model in which a vascularized inguinal lymph node (LN) flap was transferred into the ipsilateral fossa after a popliteal LN was removed; a LN dissection (LND) model in which the popliteal LN was dissected; and a control model in which a skin incision was made at the popliteal fossa and an ipsilateral inguinal LN was removed. Postoperative lymphatic flows were observed by indocyanine green lymphography and B16-F10-luc2 mouse melanoma were implanted into the ipsilateral footpad. The proportion of DCs in the transplanted nodes was measured by CD11c immunohistochemistry using digital imaging analysis 4 days after cancer implantation. Metastases to the lungs and LNs were quantitatively evaluated by luciferase assay 4 weeks after cancer implantation.

RESULTS

After VLNT, lymphatic reconnection was observed in 59.2% of mice. The proportion of DCs was significantly higher in the VLNT group with lymphatic reconnection (8.6% ± 1.0%) than in the naïve LN (4.3% ± 0.4%) (p < .001). The tumor burden of lung metastases was significantly less in the VLNT group with lymphatic reconnection compared with the LND group (p = .049).

CONCLUSIONS

Metastasis decreased in mice with reconnected lymphatics after VLNT. A possible explanation was that lymphatic restoration may have contributed to the tumor immune response by allowing DC migration to LNs.

Outcomes after microsurgical treatment of lymphedema: a systematic review and meta-analysis

BACKGROUND

Microsurgical treatment options for lymphedema consist mainly of lymphovenous anastomosis (LVA) and vascularized lymph node transfers (VLNTs). There are no standard measurements of the effectiveness of these interventions and reported outcomes vary among studies.

METHODS

A systematic review and meta-analysis were performed based on a structured search in Embase, Medline, PubMed, Cinahl, Cochrane, and ProQuest in October 2020, with an update in February 2022. Firstly, a qualitative summary of the main reported outcomes was performed, followed by a pooled meta-analysis of the three most frequently reported outcomes using a random effects model. Randomized controlled trials, prospective cohorts, retrospective cohorts, and cross-sectional and case-control studies that documented outcomes following microsurgery in adult patients were included. Studies of other surgical treatments (liposuction, radical excision, lymphatic vessel transplantation) or without reported outcomes were excluded. The study protocol was registered on PROSPERO (International Prospective Register of Systematic Reviews) (ID: CRD42020202417). No external funding was received for this review.

RESULTS

One hundred fifty studies, including 6496 patients, were included in the systematic review. The qualitative analysis highlighted the three most frequently reported outcomes: change in circumference, change in volume, and change in the number of infectious episodes per year. The overall pooled change in excess circumference across 29 studies, including 1002 patients, was -35.6% [95% CI: -30.8 to -40.3]. The overall pooled change in excess volume across 12 studies including 587 patients was -32.7% [95% CI: -19.8 to -45.6], and the overall pooled change in the number of cutaneous infections episodes per year across 8 studies including 248 patients was -1.9 [95% CI: -1.4 to -2.3]. The vast majority of the studies included were case series and cohorts, which were intrinsically exposed to a risk of selection bias.

CONCLUSION

The currently available evidence supports LVA and vascularized lymph node transfers as effective treatments to reduce the severity of secondary lymphedema. Standardization of staging method, outcomes measurements, and reporting is paramount in future research in order to allow comparability across studies and pooling of results.

Structural and functional analysis of the newt lymphatic system

Regeneration competent vertebrates such as newts and salamanders possess a weakened adaptive immune system characterized by multiple connections between the lymphatic system and the blood vascular system called lymphatic hearts. The role of lymphatic vasculature and these lymphaticovenous connections in regeneration is unknown. We used in-vivo near-infrared lymphangiography, ultra-high frequency ultrasonography, micro-CT lymphangiography, and histological serial section 3-dimentional computer reconstruction to evaluate the lymphatic territories of Cynops pyrrhogaster. We used our model and supermicrosurgery to show that lymphatic hearts are not essential for lymphatic circulation and limb regeneration. Instead, newts possess a novel intraosseous network of lymphatics inside the bone expressing VEGFR-3, LYVE-1 and CD-31. However, we were unable to show Prox-1 expression by these vessels. We demonstrate that adult newt bone marrow functions as both a lymphatic drainage organ and fat reservoir. This study reveals the fundamental anatomical differences between the immune system of urodeles and mammals and provides a model for investigating lymphatics and regeneration.

Lymphaticovenular anastomoses training model for multiple stages of lymphedema by using efferent lymphatic plexus of the mesenteric lymph node of rats

INTRODUCTION

Lymphaticovenular anastomosis (LVA) has transformed lymphedema treatment and has become an important part of the surgical therapy. LVA requires supermicrosurgical skills and unique nontraumatic techniques as the lymphatic vessel diameter of varies with the progression of lymphedema from 0.3 to 0.8 mm. However, even though several supermicrosurgical vessel anastomosis training models have been reported, only few focus on LVA including both various sizes of lymphatic vessels and lymphatic dissection. We report the establishment of a novel in-vivo LVA training model using the rat efferent lymphatic plexus of the mesenteric lymph node.

MATERIALS AND METHODS

Lymphatic vessels in the efferent lymphatic plexus of the mesenteric lymph node and mesenteric veins of 10 male Wistar rats, 572-850 g, were used for LVA in an intima-to-intima coaptation manner using 12-0 nylon suture with 4-6 stitches in an end-to-end fashion. Postoperative patency was evaluated with indigo carmine blue after completion of anastomosis. Diameters of lymphatic vessels in the plexus and recipient veins were measured.

RESULTS

The diameters of lymphatic vessels in efferent lymphatic plexus of the mesenteric lymph nodes and mesenteric veins used as recipients were measured in all 10 male rats. The mean number of lymphatic vessels included in efferent lymphatic plexus of the mesenteric lymph nodes was 7.5 (range, 5-11) and the mean diameter of the lymphatic vessels was 0.34 mm (range, 0.1-1.2 mm). The mean diameter of lymphatic vessels used for LVA was 0.46 mm (range, 0.25-0.7 mm). The mean diameter of the recipient veins was 0.49 mm (range, 0.35-0.7 mm). The postoperative patency rate after LVA was 100% (10/10).

CONCLUSION

We reported the establishment of LVA model involving the use of the efferent lymphatic plexus of the mesenteric lymph node and mesenteric veins in rats.

Clinical and Histological Effects of Partial Blood Flow Impairment in Vascularized Lymph Node Transfer

Regarding vascularized lymph node transfer (VLNT) for lymphedema, partial blood flow impairment in transferred lymph node (LN) flaps may adversely affect the therapeutic results. We investigated the clinical and histological effects of partial blood flow impairment in LN flaps. In upper extremity lymphedema cases, based on ultrasonographic examination at 2 weeks after VLNT, we compared the treatment results depending on whether the postoperative blood flow in transferred LNs was good (Group G) or poor (Group P). Novel partial ischemia and congestion of LN flap mouse models were developed to determine their histological features. In 42 cases, significant differences were observed between Group G (n = 37) and Group P (n = 5) based on the amount of volume reduction (136.7 ± 91.7 mL and 55.4 ± 60.4 mL, respectively; p = 0.04) and lymph flow recanalization rate in indocyanine green fluorescent lymphography (67.6% and 0%, respectively; p = 0.0007). In mouse models, thrombi formation in the marginal sinus and numerous Myl9/12-positive immunocompetent cells in follicles were observed in congested LNs. Blood flow maintenance in the transferred LNs is an essential factor influencing the therapeutic effect of VLNT. Postoperatively, surgeons should closely monitor blood flow in the transferred LNs, particularly in cases of congestion.

Lower Limb Lymphedema Patients Can Still Benefit from Supermicrosurgical Lymphaticovenous Anastomosis (LVA) after Vascularized Lymph Node Flap Transfer (VLNT) as Delayed Lymphatic Reconstruction-A Retrospective Cohort Study

Background: For lymphedema patients who received a vascularized lymph node flap transfer (VLNT) as their primary treatment, what are the treatment options when they seek further improvement? With recent publications supporting the use of lymphaticovenous anastomosis (LVA) for treating severe lymphedema, we examined whether LVA could benefit post-VLNT patients seeking further improvement. Methods: This retrospective cohort study enrolled eight lymphedema patients with nine lymphedematous limbs (one patient suffered from bilateral lower limb lymphedema) who had received VLNT as their primary surgery. Patients with previous LVA, liposuction, excisional therapy, or incomplete data were excluded. LVA was performed on nine lower lymphedematous limbs. Demographic data and intraoperative findings were recorded. Preoperative and postoperative limb volumes were measured with magnetic resonance volumetry. The primary outcome was the limb volume measured 6 months post-LVA. Results: The median duration of lymphedema before LVA was 10.5 (4.9–15.3) years. The median waiting time between VLNT and LVA was 41.4 (22.3–97.9) months. The median volume gained in the lymphedematous limb was 3836 (2505–4584) milliliters (mL). The median post-LVA follow-up period was 18 (6–30) months. Significant 6-month and 1-year post-LVA percentage volume reductions were found compared to pre-LVA volume (both p < 0.001). Conclusion: Based on the results from this study, the authors recommend the use of LVA as a secondary procedure for post-VLNT patients seeking further improvement.

Where does subcutaneous lymph from the chest wall flow into after mastectomy?

BACKGROUND

Changes of the lymph flow from the chest wall after mastectomy and sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (Ax) has yet to be understood. This study aimed to investigate the effect of axillary surgery on lymphatic flow from the chest wall in patients who have undergone mastectomy, including those have undergone breast reconstruction and vascularized lymph node transfer (VLNT).

METHODS

Following mastectomy in 100 breasts, the directions of lymph flow from the chest wall was compared between the SLNB omission, SLNB, Ax, and Ax followed by VLNT groups using indocyanine green (ICG) lymphography in cross-sectional study. Lymph flow on the deep epigastric artery perforator (DIEP) flap was also investigated.

RESULTS

Lymph flow directing to the ipsilateral axilla was observed more frequently after SLNB than Ax (48% vs. 12.5%; p = 0.005); however, no significant difference was observed in the frequency of contralateral axillary route adoption between them (8% vs. 15%; p = 0.65). In the VLNT group, lymph flow to the ipsilateral axilla was not observed at a significantly higher frequency than in the Ax group (12.5% vs. 12.5%, p = 1.00). On the transferred DIEP flap, the lymph flowed anterograde or retrograde parallel to the anatomic course of the lymphatic vessels.

CONCLUSION

To visualize the direction of lymph flow of the chest following mastectomy, ICG lymphography may be useful to discern the direction in which malignant neoplasms, including lymphoma, are transported and to plan for lymph flow restoration.

Technical Challenges in "Micro" Lymph Node Identification during Vascularized Submental Lymph Node Flap Harvesting

Background:

The outcome of autologous lymph node (LN) transfer has depended on the number of LNs in the donor site. Unknown accuracy of the LN counting method has thrown some doubts on the reliability of the previous statistics. This study aimed to assess the accuracy of naked eye (NK) and stereo microscopy (SM) as tools for LN count.

Methods:

In total, 40 vascularized submental LN flaps were harvested from 23 fresh cadavers. The colored polymer was injected into the external carotid arteries before the harvest. LNs in each flap were counted by NK, SM, and histology in sequential order.

Results:

An estimated 175 LNs were confirmed, 4.4 ± 1.8 per flap. NK sensitivity was 33.7% compared with that of SM at 63.5%. Both methods missed all micro-lymph nodes (micro-LNs), contributing to 5.1% (9 nodes) of all LNs. Non-LN structures (647 negative counts) were composed of fat lobules, salivary gland lobules, and muscle fibers. NK specificity was 98.0%, compared with that of SM at 96.1%. SM showed a higher false positive rate at 14.3%, compared with NK at 7.4%. False positive counts were located mostly in Ib sublevel.

Conclusions:

NK and SM are imperfect tools for LN count due to poor sensitivity. If the method needs to be applied, points of considerations are (1) undetectable micro-LNs, (2) interposition of LNs with the digastric muscle and submandibular salivary gland, (3) confusion of LNs with lobules of salivary gland supplied by glandular artery or fat lobules supplied by lobular artery.

A Novel Approach to Subcutaneous Collecting Lymph Ducts Using a Small Diameter Wire in Animal Experiments and Clinical Trials

Background: While performing microsurgery, including lymphaticovenous anastomosis (LVA) for chronic limb lymphedema, it is a common procedure to identify the subcutaneous collecting lymph ducts with near-infrared fluorescence lymphangiography (NIR) using indocyanine green. However, due to limitations such as minimum observable depth, only a few lymphatic ducts can be identified with this procedure. Hence, we developed a new smaller-diameter "lymphatic wire" (LW) that could be inserted directly into lymphatic collecting ducts of the limbs, enabling accurate identification and localization. Methods and Results: First, used the LW on the hind limbs of 6 swine, and 36 porcine lymphatic collecting ducts were identified, the outer diameter of which varied from 0.3-0.7 mm (mean 0.41 ± 0.11 mm). We could insert the LW after creating a side opening in 30 of these ducts. We encountered no difficulties during the procedure. In the pathological examination, adverse events such as valve dysfunction and perforation were not identified. Based on the results, a clinical evaluation of the LW was performed in two patients with lower extremity lymphedema, and the LW helped us identify lymphatic ducts in the subcutaneous layer, even at the sites where the NIR had proved ineffective. Conclusion: Based on our results, we suggest that the procedure for identifying lymphatic vessels using the newly developed LW is a useful technique that can be utilized before performing a LVA for lymphedema. However, further clinical study is required to develop this device and technique, for wider clinical application in the future.

SPECT/CT and fusion ultrasound to target the efferent groin lymph node for lymphatic surgery

INTRODUCTION

Pelvic lymphadenectomy (PL) causes changes to the inguinal lymph nodes with progressive loss of immune and lymphatic pump function. Efferent lymphatic vessel-to-venous anastomosis (ELVA) has been reported to address this problem. The aim of this report was to describe the feasibility of the SPECT/CT combined with ultrasound fusion imaging (UFI) to target the groin efferent lymph node (GELN) for ELVA.

PATIENTS AND METHODS

Twelve patients with lower limb lymphedema after PL were scheduled for peripheric lymphaticovenular anastomosis (LVA) combined with ELVA. All-patients were clinically ISL-stage1, with good visualization of the inguinal lymph nodes at preoperative lymphoscintigraphy. The mean patient age was 55.4 years and the mean BMI was 25.5.The mean limb circumference (MLC) was calculated before surgery and 1 year after surgery. The LymQoL-Leg questionnaire was administered before surgery and 6 months after surgery. Before surgery, the GELN was identified by SPECT/CT and its location was marked on the skin by UFI virtual navigation. Peripheric LVA sites were planned by ultrasound and indocyanine green (ICG) lymphography. Pre and postoperative MLC and LymQoL-Leg scores were compared.

RESULTS

In all-patients, the SPECT/CT succeeded at detecting and targeting the GELN. In all-patients, real-time anatomical coregistration with US was feasible, and it was possible to mark on the groin skin the depth and position of the GELN on the skin at the groin. During surgery, in every patient, we found the GELN marked before surgery and performed ELVA. We also performed two or three peripheric LVAs in every patient. The mean value of MLC decreased (38.2 ± 2.13 cm vs. 36.33 ± 2.14 cm; p = .04) and the mean score of the LymQoL-Leg questionnaire improved (9.3 ± 1.7 vs. 7.7 ± 1.1; p = .02).

CONCLUSION

SPECT/CT combined with UFI is feasible for the preoperative identification of GELN for ELVA.

Cancer-associated secondary lymphoedema

Lymphoedema is an oedematous condition with a specific and complex tissue biology. In the clinical context of cancer, the pathogenesis of lymphoedema ensues most typically from the modalities employed to stage and treat the cancer (in particular, surgery and radiotherapy). Despite advances in cancer treatment, lifelong lymphoedema (limb swelling and the accompanying chronic inflammatory processes) affects approximately one in seven individuals treated for cancer, although estimates of lymphoedema prevalence following cancer treatment vary widely depending upon the diagnostic criteria used and the duration of follow-up. The natural history of cancer-associated lymphoedema is defined by increasing limb girth, fibrosis, inflammation, abnormal fat deposition and eventual marked cutaneous pathology, which also increases the risk of recurrent skin infections. Lymphoedema can substantially affect the daily quality of life of patients, as, in addition to aesthetic concerns, it can cause discomfort and affect the ability to carry out daily tasks. Clinical diagnosis is dependent on comparison of the affected region with the equivalent region on the unaffected side and, if available, with pre-surgical measurements. Surveillance is indicated in this high-risk population to facilitate disease detection at the early stages, when therapeutic interventions are most effective. Treatment modalities include conservative physical strategies that feature complex decongestive therapy (including compression garments) and intermittent pneumatic compression, as well as an emerging spectrum of surgical interventions, including liposuction for late-stage disease. The future application of pharmacological and microsurgical therapeutics for cancer-associated lymphoedema holds great promise.