Magnetic resonance lymphography as three-dimensional navigation for lymphaticovenular anastomosis in patients with leg lymphedema

Magnetic resonance lymphography findings across different clinical stages of lower limb lymphedema

OBJECTIVE

To investigate the findings on lower limb lymphedema using magnetic resonance lymphography (MRL).

METHODS

MRL was used to record the lymphatic vessel morphology, distribution of lymphatic vessels, dermal backflow (DBF), and morphology of inguinal lymph nodes in 112 patients (175 affected limbs) with lower limb lymphedema at different clinical stages (according to the International Society of Lymphology staging criteria 2020).

RESULTS

The lymphatic vessel morphology significantly differed at different clinical stages (X2 =59.306; P = 0.000). ISL stage I is dominated by "scattered beads" and "branch-like" distribution, ISL stage Ⅱ has tree branch or "capillary-like" distribution, and ISL stage Ⅲ primarily has a capillary pattern and contrast agent accumulation in the foot. There were statistically significant differences in the distribution of lymphatic vessels and DBF in different clinical stages. Distribution of the enhanced lymphatic vessels was distal to the knee in ISL stage I, involved areas below the knee joint or the whole limb in ISL stage II, and involved the whole limb in ISL stage III (X2 =44.591; P = 0.000). With the progression of edema, DBF severity increased (X2 =76.416; P = 0.000).

CONCLUSION

MRL revealed the morphology and distribution of lymphatic vessels and detected abnormal inguinal lymph nodes in patients at different stages of lymphedema, which can be used as reference information for surgical treatment.

Progression of fluid infiltration on non-contrast magnetic resonance imaging in breast cancer-related lymphedema: A comparative analysis with indocyanine green lymphography

BACKGROUND

Non-contrast magnetic resonance imaging (NMRI) has been reported as valuable for the assessment of lymphedema. However, the correlation between NMRI findings and indocyanine green lymphography (ICG-L) findings remains elusive.

METHODS

This single-center retrospective study included 26 patients diagnosed with breast cancer-related lymphedema. We examined the prevalence of fluid infiltration in eight regions of the upper extremity, the type of fluid distribution, and the dominant segment of edema on NMRI in comparison to the ICG-L stage. Statistical analysis was performed using the Cochran-Armitage trend test, Spearman's rank correlation test, and Fisher's exact test.

RESULTS

The regional fluid infiltration significantly increased with the progression of the ICG-L stage (hand, forearm, elbow, and upper arm: p = 0.003, <0.001, <0.001, and <0.001, respectively). The fluid distribution significantly advanced with the progression of the ICG-L stage as follows (rs = 0.80; p < 0.001): no edema in ICG-L stage 0, edema in either the hand or elbow in ICG-L stage I, edemas in both the elbow and hand in ICG-L stage II, three segmental edemas centered on the forearm or elbow in ICG-L stage III, and edema encompassing the entire upper limb in ICG-L stage IV-V. Additionally, the dominant segment of edema tended to shift from the hand to the elbow and further to the forearm as the ICG-L stage progressed (p < 0.001).

CONCLUSIONS

Fluid infiltration observed on NMRI exhibited distinct patterns with the progression of the ICG-L stage. We believe that anatomical information regarding fluid distribution would potentially contribute to optimizing surgical efficacy.

Preoperative photoacoustic versus indocyanine green lymphography in lymphaticovenular anastomosis outcomes for lower extremity lymphedema: A pilot study

BACKGROUND

Identification of the proper lymphatics is important for successful lymphaticovenular anastomosis (LVA) for lymphedema; however, visualization of lymphatic vessels is challenging. Photoacoustic lymphangiography (PAL) can help visualize lymphatics more clearly than other modalities. Therefore, we investigated the usefulness of PAL and determined whether the clear and three-dimensional image of PAL affects LVA outcomes.

METHODS

We recruited 22 female patients with lower extremity lymphedema. The operative time, number of incisions, number of anastomoses, lymphatic vessel detection rate (number of functional lymphatics identified during the operation/number of incisions), and limb volume changes preoperatively and 3 months postoperatively were compared retrospectively. The patients were divided according to whether PAL was performed or not, and results were compared between those undergoing PAL (PAL group; n = 10) and those who did not (near-infrared fluorescence [NIRF] group, n = 12).

RESULTS

The mean age of the patients was 55.9 ± 15.1 years in the PAL group and 50.7 ± 14.9 years in the NIRF group. One patient in the PAL group and three in the NIRF group had primary lymphedema. Eighteen patients (PAL group, nine; and NIRF group, nine) had secondary lymphedema. Based on preoperative evaluation using the International Society of Lymphology (ISL) classification, eight patients were determined to be in stage 2 and two patients in late stage 2 in the PAL group. In contrast, in the NIRF group, one patient was determined to be in stage 0, three patients each in stage 1 and stage 2, and five patients in late stage 2. Lymphatic vessel detection rates were 93% (42 LVAs and 45 incisions) and 83% (50 LVAs and 60 incisions) in the groups with and without PAL, respectively (p = 0.42). Limb volume change was evaluated in five limbs of four patients and in seven limbs of five patients in the PAL and NIRF groups as 336.6 ± 203.6 mL (5.90% ± 3.27%) and 52.9 ± 260.7 mL (0.71% ± 4.27%), respectively. The PAL group showed a significant volume reduction. (p = .038).

CONCLUSIONS

Detection of functional lymphatic vessels on PAL is useful for treating LVA.

Changes in intracellular water volume after leg lymphedema onset and lymphaticovenular anastomosis as its surgical intervention

OBJECTIVE

To clarify the changes in the intracellular water (ICW) volume in lymphedema-affected legs after lymphedema onset and its surgical intervention (ie, lymphaticovenular anastomosis [LVA]), we investigated the changes in body water composition using bioelectrical impedance analysis.

METHODS

This retrospective case series included 41 women with unilateral secondary leg lymphedema. The volume changes in the ICW and extracellular water (ECW) of the affected leg were measured using an InBody S10 (InBody Co, Ltd) multifrequency bioelectrical impedance analyzer, at both lymphedema onset and 1 year after LVA.

RESULTS

The volume increase with leg lymphedema onset was comparable between the ECW and ICW (0.59 L vs 0.56 L; 95% confidence interval [CI], -0.02 to 0.06; P = .27), and the increase rate was higher for ECW (35.3% vs 22.1%; 95% CI, 9.3%-17.2%; P < .001). The volume reduction at 1 year after LVA was comparable between ECW and ICW (0.23 L vs 0.27 L; 95% CI, -0.08 to 0.02; P = .20), and the reduction rate was higher for ECW (8.7% vs 7.0%, 95% CI, 0.04%-3.2%; P = .044). The volume difference between ICW and ECW remained constant throughout the six measurements before and after LVA (F[3.01, 120.20] = 1.85; P < .14).

CONCLUSIONS

Leg LVA reduced ICW in the lymphedematous leg. The onset of leg lymphedema increased ECW and ICW in the affected limb, and LVA decreased both ECW and ICW. The volume change in the affected leg was comparable between ECW and ICW at both lymphedema onset and after LVA. However, the rate of change was higher for ECW. The volume difference between ICW and ECW remained constant. Using bioelectrical impedance analysis, alterations in ICW volume were detected in the legs affected by lymphedema, both after the onset of lymphedema and after LVA intervention.

Lymphatic flow velocity is a predictor of functional lymphatic vessels for lymphaticovenous anastomosis

BACKGROUND

Indocyanine green (ICG) lymphography is widely used to localize functional lymphatic vessels for lymphaticovenous anastomosis (LVA); however, flow velocity is rarely assessed. We aimed to evaluate the correlation between lymphatic flow velocity and the presence of functional lymphatic vessels.

METHODS

Data of a total of 924 lymphatic vessels from 273 lymphedema patients who underwent LVA between July 2018 and December 2020 were retrospectively reviewed. Lymph flow velocity was defined by considering the most proximal anatomic location enhanced by ICG at 30 min after injection and categorized into four groups; grade 1 (foot or hand), grade 2 (below knee or elbow), grade 3 (at/above knee or eblow), or grade 4 (axilla or groin). The presence of functional lymphatic vessels, which showed lymphatic fluid flow when the vessels were cut for anastomosis, was compared between the four groups.

RESULTS

A higher rate of functional lymphatic vessels was observed among lymphatic vessels with grade 3 or 4 flow velocity compared with those with grade 1 or 2 flow velocity (67.5% vs. 44.5%; p < 0.001). These findings were consistent with the observations for lymphatic vessels with a non-linear pattern in ICG lymphography (59.4% vs. 26.5%; p < 0.001). The rate of completion of LVA at surgical sites in extremities with grade 3 or 4 flow velocity was 88.1% compared with 65.8% in extremities with grade 1 or 2 velocity (p < 0.001).

CONCLUSIONS

Lymph flow velocity grading can be a simple and easy adjunctive method to determine indication for LVA in extremities with lymphedema.

Comparative Analysis of Preoperative High Frequency Color Doppler Ultrasound versus MR Lymphangiography versus ICG Lymphography of Lymphatic Vessels in Lymphovenous Anastomosis

BACKGROUND

 Despite the extensive use of various imaging modalities, there is limited literature on comparing the reliability between indocyanine green (ICG) lymphography, MR Lymphangiogram (MRL), and high frequency color Doppler ultrasound (HFCDU) to identify lymphatic vessels.

METHOD

 In this study of 124 patients, the correlation between preoperative image findings to the actual lymphatic vessel leading to lymphovenous anastomosis (LVA) was evaluated. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and simple detection were calculated. Subgroup analysis was also performed according to the severity of lymphedema.

RESULTS

 Total of 328 LVAs were performed. The HFCDU overall had significantly higher sensitivity for identifying lymphatic vessels (99%) over MRL (83.5%) and ICG lymphography (82.3%)(p < 0.0001). Both ICG lymphography and HFCDU had 100% specificity and PPV. The NPV was 3.6%, 6.5% and 57.1% respectively for MRL, ICG lymphography, and HFCDU. All modalities showed high sensitivity for early stage 2 lymphedema while HFCDU showed a significantly higher sensitivity for late stage 2 (MRL:79.7%, ICG:83.1%, HFCDU:97%) and stage 3 (MRL:79.7%, ICG:79.7%, HFCDU:100%) over the other two modalities (p < 0.0001).

CONCLUSION

 This study demonstrated while all three modalities are able to provide good information, the sensitivity may alter as the severity of lymphedema progresses. The HFCDU will provide the best detection for lymphatic vessels throughout all stages of lymphedema. However, as each modality provides different and unique information, combining and evaluating the data according to the stage of lymphedema will be able to maximize the chance for a successful surgical outcome.

Imaging of the Lymphatic Vessels for Surgical Planning: A Systematic Review

BACKGROUND

Secondary lymphedema is a common complication after surgical or radiotherapeutic cancer treatment. (Micro) surgical intervention such as lymphovenous bypass and vascularized lymph node transfer is a possible solution in patients who are refractory to conventional treatment. Adequate imaging is needed to identify functional lymphatic vessels and nearby veins for surgical planning.

METHODS

A systematic literature search of the Embase, MEDLINE ALL via Ovid, Web of Science Core Collection and Cochrane CENTRAL Register of Trials databases was conducted in February 2022. Studies reporting on lymphatic vessel detection in healthy subjects or secondary lymphedema of the limbs or head and neck were analyzed.

RESULTS

Overall, 129 lymphatic vessel imaging studies were included, and six imaging modalities were identified. The aim of the studies was diagnosis, severity staging, and/or surgical planning.

CONCLUSION

Due to its utility in surgical planning, near-infrared fluorescence lymphangiography (NIRF-L) has gained prominence in recent years relative to lymphoscintigraphy, the current gold standard for diagnosis and severity staging. Magnetic resonance lymphography (MRL) gives three-dimensional detailed information on the location of both lymphatic vessels and veins and the extent of fat hypertrophy; however, MRL is less practical for routine presurgical implementation due to its limited availability and high cost. High frequency ultrasound imaging can provide high resolution imaging of lymphatic vessels but is highly operator-dependent and accurate identification of lymphatic vessels is difficult. Finally, photoacoustic imaging (PAI) is a novel technique for visualization of functional lymphatic vessels and veins. More evidence is needed to evaluate the utility of PAI in surgical planning.

Outcomes of Lymphovenous Anastomosis for Lower Extremity Lymphedema: A Systematic Review

Lymphovenous anastomosis (LVA) is a microsurgical treatment for lymphedema of the lower extremity (LEL). This study systematically reviews the most recent data on outcomes of various LVA techniques for LEL in diverse patients.

METHODS

A comprehensive literature search was conducted in the Ovid MEDLINE, Ovid EMBASE, and Scopus databases to extract articles published through June 2021. Studies reporting data on objective postoperative improvement in lymphedema and/or subjective improvement in quality of life for patients with LEL were included. Extracted data comprised demographics, number of patients and lower limbs, duration of symptoms before LVA, surgical technique, duration of follow-up, and objective and subjective outcomes.

RESULTS

A total of 303 articles were identified and evaluated, of which 74 were ultimately deemed eligible for inclusion in this study, representing 6260 patients and 2554 lower limbs. The average patient age ranged from 22.6 to 76.14 years. The duration of lymphedema before LVA ranged from 12 months to 11.4 years. Objective rates of improvement in lymphedema ranged from 23.3% to 100%, with the greatest degree of improvement seen in patients with early-stage LEL.

CONCLUSIONS

LVA is a safe and effective technique for the treatment of LEL of all stages. Several emerging techniques and variations may lead to improved patient outcomes.

Surgical Applications of Lymphatic Vessel Visualization Using Photoacoustic Imaging and Augmented Reality

Lymphaticovenular anastomosis (LVA) is a widely performed surgical procedure for the treatment of lymphedema. For good LVA outcomes, identifying lymphatic vessels and venules is crucial. Photoacoustic lymphangiography (PAL) is a new technology for visualizing lymphatic vessels. It can depict lymphatic vessels at high resolution; therefore, this study focused on how to apply PAL for lymphatic surgery. To visualize lymphatic vessels, indocyanine green was injected as a color agent. PAI-05 was used as the photoacoustic imaging device. Lymphatic vessels and veins were visualized at 797- and 835-nm wavelengths. First, it was confirmed whether the branching of the vasculature as depicted by the PAL was consistent with the actual branching of the vasculature as confirmed intraoperatively. Second, to use PAL images for surgical planning, preoperative photoacoustic images were superimposed onto the patient limb through augmented reality (AR) glasses (MOVERIO Smart Glass BT-30E). Lymphatics and venule markings drawn using AR glasses were consistent with the actual intraoperative images obtained during LVA. To anastomose multiple lymphatic vessels, a site with abundant venous branching was selected as the incision site; and selecting the incision site became easier. The anatomical morphology obtained by PAL matched the surgical field. AR-based marking could be very useful in future LVA.

Application of Photoacoustic Imaging for Lymphedema Treatment

Background  Lymphatic vessels are difficult to identify using existing modalities as because of their small diameter and the transparency of the lymph fluid flowing through them.

Methods  Here, we introduce photoacoustic lymphangiography (PAL), a new modality widely used for lymphedema treatment, to observe limb lymphatic vessels. The photoacoustic imaging system used in this study can simultaneously visualize lymphatic vessels and veins with a high resolution (0.2 mm) and can also observe their three-dimensional relationship with each other.

Results  High-resolution images of the lymphatic vessels, detailed structure of the dermal back flow, and the three-dimensional positional relationship between the lymphatic vessels and veins were observed by PAL.

Conclusion  The clear image provided by PAL could have a major application in pre- and postoperative use during lymphaticovenular anastomosis for lymphedema treatment.

Advances in surgical treatment of lymphedema

An estimated 250 million people worldwide suffer from lymphedema. In the past, the firstline option for treatment was nonsurgical management, either in the form of compression garments or wrapping, or comprehensive decongestive therapy, with debulking surgery reserved for the more advanced cases. However, with improvements in microsurgical techniques and imaging modalities, surgical intervention is increasingly being utilized. This review highlights recent advancements in the surgical treatment of lymphedema, specifically focusing on improvements in imaging, surgical techniques, and prevention of lymphedema.

Impact of Magnetic Resonance Lymphography on Lymphaticolvenular Anastomosis for Lower-Limb Lymphedema

BACKGROUND

 Although several investigations have described the safety, utility, and precision of magnetic resonance lymphography (MRL) as a preoperative examination for lymphaticovenular anastomosis (LVA), it is unclear how much MRL assistance impacts LVA results. The present study aimed to clarify the outcome of MRL-assisted LVA for leg lymphedema using body water measurements obtained by bioelectrical impedance analysis.

METHODS

 The water reductive effect of MRL-assisted LVA in female secondary leg lymphedema patients was compared with that of non-MRL-assisted controls in this retrospective study. In the MRL-assisted group, all LVA candidates underwent MRL prior to surgery, and the lymphatic vessels to be anastomosed were primarily determined by MRL findings. The body water composition of the treated legs was assessed before LVA and at 6 months postoperatively using a multi-frequency bioelectrical impedance analyzer.

RESULTS

 Twenty-three patients in the MRL-assisted study group and an equal number in the non-MRL-assisted control group were analyzed. Although mean leg water volume before LVA, mean excess water volume of the affected leg before LVA, and number of anastomoses created were comparable between the groups, the water volume reduction (1.02 L versus 0.49 L; 95% confidence interval [CI]: 0.03-1.03, p < 0.05) and edema reduction rate (46.7% versus 27.2%; 95% CI: 3.7-35.5%, p < 0.05) in the MRL-assisted group were significantly greater than in controls.

CONCLUSION

 Preoperative MRL-assisted lymph vessel visualization and selection appeared to significantly enhance the water reductive effect of LVA for International Society of Lymphology classification stage 2 leg lymphedema. MRL also helped to reliably identify lymphatic vessels for anastomosis. Without increasing the number of anastomoses, LVA could be performed more effectively by better detecting stagnant lymphatic vessels using MRL.