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Digital Volumetric Measurements Based on 3D Scans of the Lower Limb: A Valid and Reproducible Method for Evaluation in Lymphedema Therapy

BACKGROUND

Exact quantification of volumetric changes of the extremities is difficult and often error-prone. The aim of this study was to establish a standardized method based on 3-dimensional (3D) scans. Furthermore, this study tests the method in terms of reproducibility and evaluates volume changes after surgical therapy in patients suffering from lymphedema on the lower extremity.

METHODS

3D scans of the lower limb were performed with a mobile 3D scanner; "repeatability" and "interobserver reliability" of digital volumetry were tested. Furthermore, the method was applied on 31 patients suffering from chronic lymphedema.

RESULTS

Calculations of repeatability of the volume based on 20 3D scans of the same lower leg showed a mean volume of 2.488 ± 0.011 liters (range: 2.470-2.510). The mean volume of the different examiners did not differ significantly (F(2,18) = 1.579, P = 0.233). The paired t-test showed a significant mean volume decrease of 375 mL (95% confidence interval = 245/505 mL) between pretreatment and post-treatment (t (30) = 5.892, P < 0.001).

CONCLUSIONS

3D volumetry is a noninvasive, easy, and quick method to assess volume changes of the lower leg. Other than the low costs, it is reproducible and precise and therefore ideal for evolution of therapy in lymphedema.

Patient characteristics may affect the lymphatic staining ability of Indocyanine green and Patent blue during lymphaticovenous anastomosis

BACKGROUND

The use of dyes like Indocyanine green (ICG) and Patent blue facilitates the identification of lymphatic vessels during lymphaticovenous anastomosis (LVA) surgery. However, some patients experience "staining failure". In these cases, no stained lymphatic vessels can be detected, making supermicrosurgical LVA even more complex.

OBJECTIVE

This study aims to investigate patient-related factors that may interfere with lymphatic vessel staining during LVA.

METHODS

A retrospective study was conducted on 30 patient charts, focusing on patient characteristics and the staining quality of ICG and Patent blue dye. Statistical analyses were performed to identify correlations between variables.

RESULTS

Significant correlations were found between higher age and secondary lymphedema, longer duration of lymphedema in male patients until surgery and reoccurring cellulitis and Patent blue staining. Notably, recurrent infections to the lymphatic system resulted in inferior staining ability during LVA surgery.

CONCLUSIONS

Due to staining failure the detection of functional lymphatic vessels remains challenging in LVA surgery. A more extensive preoperative workup is recommended for patients with recurrent cellulitis to optimize surgical feasibility and procedure quality in LVA treatment for lymphedema.

Investigation of optimizing indocyanine green solution for in vivo lymphatic research using near-infrared fluorescence indocyanine green lymphangiography

Despite the tireless efforts of many researchers in lymphatic research, indocyanine green (ICG) solution conditions suitable for lymphatic circulation tests have not been perfectly established yet. We aimed to investigate the optimal in vivo conditions of ICG solution to avoid photobleaching and quenching effects, which may affect the accuracy of lymphatic circulation evaluation. After ICG fluorescence intensity (or ICG intensity) was assessed under different in vitro conditions, the image quality of brachial lymph nodes (LNs) and collecting lymphatic vessels (LVs) in eight rats was investigated. The in vitro results showed that ICG intensity depends on concentration and time in various solvents; however, the brightest intensity was observed at a concentration of 8-30 μg/mL in all solvents. ICG concentration in the albumin (bovine serum albumin; BSA) solution and rat's plasma showed more than two times higher fluorescence intensity than in distilled water (DW) in the same range. However, saline reduced the intensity by almost half compared to DW. In the in vivo experiment, we obtained relatively high-quality images of the LNs and LVs using ICG in the BSA solution. Even at low concentrations, the result in the BSA solution was comparable to those obtained from high-concentration solutions commonly used in conventional circulation tests. This study provides valuable information about the conditions for optimal ICG intensity in near infrared fluorescence indocyanine green (NIRF-ICG) lymphangiography, which may be useful not only for the diagnosis of lymphatic circulation diseases such as lymphedema but also for preclinical research for the lymphatic system.

The Usefulness of a Three-Microneedle Device for Indocyanine Green Fluorescence Lymphography

Background: Indocyanine green (ICG) fluorescence lymphography is widely used to diagnose lymphedema. There is little consensus on the appropriate injection method for ICG fluorescence lymphangiography. We used a three-microneedle device (TMD) for skin injection of ICG solution and investigated its usefulness. Methods and Results: Thirty healthy volunteers were injected with ICG solution using a 27-gauge (27G) needle in one foot and a TMD in the other foot. Injection-related pain was evaluated using the Numerical Rating Scale (NRS) and Face Rating Scale (FRS). The skin depth of the injected ICG solution was evaluated by injecting the solution into the skin of amputated lower limbs using a 27G needle or TMD using ICG fluorescence microscopy. The median and interquartile range of the NRS scores was 3 (3-4) and 2 (2-4) in the 27G needle and TMD groups, respectively; that of the FRS scores was 2 (2-3) and 2 (1-2) in the 27G needle and TMD groups, respectively. Injection-related pain was significantly lower with the TMD than with the 27G needle. The lymphatic vessels were similarly visible using both needles. The depth of the ICG solution varied for each injection with a 27G needle (400-1200 μm) and was consistent at ∼300-700 μm below the skin surface using the TMD. Injection depth was significantly different between the 27G needle and the TMD. Conclusions: Injection-related pain decreased using the TMD, and ICG solution depth was consistent on fluorescence lymphography. A TMD may be useful for ICG fluorescence lymphography. Clinical Trials Registry (UMIN-CTR; ID: UMIN000033425).

Quality of Life evaluation and lack of correlation with volumetric results after lymphovenous anastomoses in lymphedema therapy of the lower extremity

OBJECTIVE

Chronic primary or secondary lymphedema has a huge impact on quality of life (QOL) because of associated swelling, pain, decreased range of motion, depression and anxiety, and generally requires numerous adaptations. Many studies have shown a positive objective effect of lymphovenous anastomoses (LVAs) on chronic lymphedema. In this study, we assessed the effect of LVAs on QOL in patients with primary or secondary lymphedema of the lower extremity 6 months after surgery, and examine the correlation between changes in QOL and volumetric measurements.

METHOD

Only patients with either primary or secondary lymphedema of the lower extremity who had LVAs were included in the study. To assess QOL, a specially designed questionnaire based on the "Lymphedema Quality of Life Inventory" (LyQLI) was used to evaluate the subjective therapeutic results from the patients' perspectives. Objective therapy success was assessed by 3D volumetric measurements of the lower leg. Measuring points, for both subjective and objective measurements, were the day before and 6 months after therapy.

RESULTS

The mean volume change 6 months after LVAs was -6.5% (sd 5.6, p < 0.001). A significantly better quality of life in terms of physical (37.6%, sd 25.2) and psychosocial (27.0%, sd 43.0) suffering as well as practical restrictions (22.3%, sd 24.8) was found (p values < 0.001). No correlation was found between QOL improvement and volume decrease (p values > 0.05).

CONCLUSION

In patients suffering from lymphedema of the lower extremity, lymphovenous anastomoses lead to a significant volumetric decrease and quality of life improvement six months after treatment with no demonstrable relationship between QOL improvement and volume reduction.