Lymphatic vessel-to-isolated-vein anastomosis for secondary lymphedema in a canine model

Optimizing Outcomes in Lymphedema Reconstruction

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Describe current surgical techniques for treating primary and secondary lymphedema. 2. Optimize the surgical care of patients with lymphedema.

SUMMARY

Over the past decade, significant advances have been made in the surgical treatment of lymphedema. The most notable changes have been the reintroduction and evolution of physiologic techniques, including lymphovenous bypass-sometimes referred to as lymphovenous anastomosis in the literature-and vascularized lymph node transplant. These surgical modalities are now often used as first-line surgical options or may be combined with nonphysiologic approaches, including direct excision and suction-assisted lipectomy. Surgeons continue to debate the most appropriate sequence and combination of surgical treatment, particularly for patients at both extremes of the severity spectrum. Furthermore, debate remains around the need to apply different treatment approaches for patients with upper versus lower extremity involvement and primary versus secondary cause. In this article, we provide a summary of the surgical techniques currently used for both primary and secondary lymphedema and provide our recommendations for optimizing the surgical care of patients with lymphedema.

Restoration of lymph flow by flap transfer can prevent severe lower extremity lymphedema after inguino-pelvic lymphadenectomy

PURPOSE

Severe lymphedema is difficult to treat because of the associated extensive scar formation. Therefore, preventing scar formation might alleviate the severity of lymphedema following lymphadenectomy. In this study, we evaluated the usefulness of flap transfer, performed immediately after lymphadenectomy, for preventing scar formation.

METHODS

Twenty-three patients with subcutaneous malignancy in a lower extremity, who underwent inguino-pelvic lymphadenectomy, were divided into groups based on whether flap transfer was performed. The severity of lymphedema was categorized according to the ratio of the circumference of the affected extremity to that of the unaffected extremity, as mild (< 20% increase in volume), moderate (20-40%), or severe (> 40%).

RESULTS

In the 18 patients who underwent lymphadenectomy without flap transfer, lymphedema was classified as mild in 7, moderate in 7, and severe in 4. In the five patients who underwent lymphadenectomy with flap transfer, lymphedema was classified as mild in 4 and moderate in 1. This difference between the groups did not reach significance.

CONCLUSIONS

The findings of this study suggest that flap transfer may help prevent scar formation and contribute to the restoration of lymph flow after lymphadenectomy.

Animal Models of Secondary Lymphedema: New Approaches in the Search for Therapeutic Options

Secondary lymphedema is still a worldwide problem. Symptomatic approaches to lymphedema therapy have been mainly used, with complete decongestive therapy as the cornerstone. Due to a lack of regenerative therapy, researchers have established various animal models to obtain insights into pathomechanisms and to reveal the best therapeutic option. Since the first reproducible and reliable animal model of lymphedema was reported in dogs, the technique of circumferential excision of lymphatic tissue has been translated mainly to rodents to induce secondary lymphedema. In these models, various promising pharmacological and surgical approaches have been investigated to improve secondary lymphedema therapy. Imaging modalities are crucial to detect the extent of lymphatic dysfunction and decide the best therapy. The gold standard of lymphoscintigraphy is currently limited by poor spatial resolution and lack of quantification. Animal models could help to bridge a gap in improving morphological correlation and quantifying lymphatic functionality. This review summarizes the animal models used in lymphatic research and focuses on new therapeutic options and requirements for imaging modalities to visualize the lymphatic system.

Animal models in surgical lymphedema research--a systematic review

BACKGROUND

Chronic secondary lymphedema is a well-known complication in oncologic surgery. Autologous lymph node transplantation, lymphovenous anastomosis, and other lymphatic surgeries have been developed in the last decades with rising clinical application. Animal models to explore the pathophysiology of lymphedema and microsurgical interventions have reached great popularity, although the induction of stable lymphedema in animals is still challenging. The aim of this review was to systematically assess lymphedema animal models and their potential use to study surgical interventions.

MATERIALS AND METHODS

A systematic review according to the PRISMA guidelines was performed without time or language restriction. Studies describing new or partially new models were included in chronological order. Models for primary and secondary lymphedema were assessed, and their potential for surgical procedures was evaluated.

RESULTS

The systematic search yielded 8590 discrete articles. Of 180 articles included on basis of title, 84 were excluded after abstract review. Ninety-six were included in the final analysis with 24 key articles.

CONCLUSIONS

No animal model is perfect, and many models show spontaneous lymphedema resolution. The rodent limb appears to be the most eligible animal model for experimental reconstruction of the lymphatic function as it is well accessible for vascularized tissue transfer. There is a need for standardized parameters in experimental lymphedema quantification. Also, more permanent models to study the effect of free vascularized lymph node transfer are needed.

Lymphovenous microsurgical shunts in treatment of lymphedema of lower limbs: a 45-year experience of one surgeon/one center

RATIONALE

The use of microsurgical lymphovenous shunts is one of the generally accepted treatments for limb lymphedema.

AIM

The 45-year personal experience of one surgeon in indications, technique and results of lymphovenous shunt operations in lower limb lymphedema of varying etiology is presented.

MATERIAL

One thousand three hundred patients were followed up in the period 1966-2011. Patients were classified into groups according to the etiology of lymphedema as postinflammatory/posttraumatic, postsurgical, idiopathic and hyperplastic. Decrease in limb circumference, heaviness and pain, and increase in joint flexing were evaluated.

RESULTS

The most satisfactory results, reaching 80-100% improvement, were obtained in the congenital non-hereditary hyperplastic lymphedema group, with large lymphatics not previously damaged by infection. Results were also satisfactory in the group of cancer patients after iliac lymphadenectomy, reaching 80%. A less satisfactory outcome was observed in the postinflammatory group, not exceeding 30-40%. In idiopathic lymphedema results were satisfactory in only a few cases.

CONCLUSIONS

Patients with lymphedema with local segmental obstruction but still partly patent distal lymphatics and without an active inflammatory process in the skin, subcutaneous tissue and lymph vessels present satisfactory results.

Optical monitoring of microlymphatic disturbances during experimental lymphedema

BACKGROUND

Rat mesentery has been widely used to study microvascular functions. The goal of this work is to extend this animal model to monitor blood and lymph microvessel function during lymphedema.

METHODS AND RESULTS

Lymphedema is created by microsurgical removal of regional lymph nodes (lymphadenectomy) or ligation of the collecting vein. Water volume in mesenteric tissue, microvessel diameters, phasic contraction, valve function, lymph flow velocity, and cell migration were analyzed during lymphedema development. Dynamic observation of water amount after lymphadenectomy revealed increasing edema from 30 min to 1 week; greatest degree of edema at one week, and gradual decrease in edema from 1 to 11 weeks. These effects were accompanied by acute constriction of lymph vessels and slowing of lymph flow velocity, switching to dilation and appearance of new blood capillaries at week 1, progressing to dilation and degenerative changes of the microlymphatic wall at week 4, and, finally, leading to lymphatic fibrosis and lymphangiogenesis at week 11. Acute venous insufficiency (30 min after vein ligation) led to significant edema, decreasing blood flow velocity to stasis, and output of erythrocytes from venules to interstitium, with further movement to microlymphatics and regional lymph nodes.

CONCLUSIONS

Rat mesentery as an animal model in combination with an advanced optical imaging system is valuable in studying microlymphatic disturbances in mesentery during the development of experimental lymphedema from latent period to chronic stages, including monitoring of individual cell dislocation with high resolution optical imaging.

Advances in small animal mesentery models for in vivo flow cytometry, dynamic microscopy, and drug screening

Using animal mesentery with intravital optical microscopy is a well-established experimental model for studying blood and lymph microcirculation in vivo. Recent advances in cell biology and optical techniques provide the basis for extending this model for new applications, which should generate significantly improved experimental data. This review summarizes the achievements in this specific area, including in vivo label-free blood and lymph photothermal flow cytometry, super-sensitive fluorescence image cytometry, light scattering and speckle flow cytometry, microvessel dynamic microscopy, infrared (IR) angiography, and high-speed imaging of individual cells in fast flow. The capabilities of these techniques, using the rat mesentery model, were demonstrated in various studies; e.g., real-time quantitative detection of circulating and migrating individual blood and cancer cells, studies on vascular dynamics with a focus on lymphatics under normal conditions and under different interventions (e.g. lasers, drugs, nicotine), assessment of lymphatic disturbances from experimental lymphedema, monitoring cell traffic between blood and lymph systems, and high-speed imaging of cell transient deformability in flow. In particular, the obtained results demonstrated that individual cell transportation in living organisms depends on cell type (e.g., normal blood or leukemic cells), the cell’s functional state (e.g., live, apoptotic, or necrotic), and the functional status of the organism. Possible future applications, including in vivo early diagnosis and prevention of disease, monitoring immune response and apoptosis, chemo- and radio-sensitivity tests, and drug screening, are also discussed.

Long-Term Results of Microscopic Lymphatic Vessel-Isolated Vein Anastomosis for Secondary Lymphedema of the Lower Extremities

PURPOSE

To evaluate the effectiveness of microscopic lymphatic vessel-isolated vein anastomosis in patients with secondary obstructive lymphedema of a lower extremity, refractory to nonoperative management.

METHODS

Nine women suffered from nonpitting edema of one or both legs (11 limbs) after radical hysterectomy with postoperative irradiation for uterine cancer. The indications for this operation were repeated cellulitis and severe nonpitting edema impairing limb function. Under microscopy of 3.2 on average, the identified lymphatic vessels were anastomosed to an isolated saphenous vein using the pull-through technique with modifications.

RESULTS

The follow-up period ranged from 21 to 87 months and the operation achieved excellent reduction, of more than 5 cm, in six limbs; good reduction, of 2-5 cm, in two limbs; and poor reduction, of less than 2 cm, in three limbs. The frequency of cellulitis decreased from 2.4 infections per patient per year to 0.2 infections per patient per year.

CONCLUSION

These results show that microscopic lymphatic vessel-isolated vein anastomosis is a minimally invasive operation, with good long-term effects, making it the treatment of choice for intractable secondary lymphedema of the lower extremities refractory to physiotherapy.