Photoacoustic lymphangiography provided a detailed, three-dimensional representation of the lymphatic vessels in the calf and their relationship with the surrounding venules. Background Detailed visualization of the lymphatic vessels would greatly assist in the diagnosis and monitoring of lymphatic diseases and aid in preoperative planning of lymphedema surgery and post...

Background Dermal backflow (DBF), which refers to lymphatic reflux due to lymphatic valve insufficiency, is a diagnostic finding in lymphedema. However, the three-dimensional structure of DBF remains unknown. Photoacoustic lymphangiography (PAL) is a new technique that enables the visualization of the distribution of light-absorbing molecules, such as hemoglobin or indocyanine green (ICG), and can provide three-dimensional images of superficial lymphatic vessels and the venous system. This study reports the use of PAL to visualize DBF structures in the extremities of patients with lymphedema after cancer surgery. Methods Patients with a clinical or lymphographic diagnosis of lymphedema who previously underwent surgery for cancer at one of two participating hospitals were included in this study. PAL was performed using the PAI-05 system. ICG was administered subcutaneously in the affected hand or foot, and ICG fluorescence lymphography was performed using a nearinfrared camera system prior to PAL. Results Between April 2018 and January 2019, 21 patients were enrolled and examined using PAL. The DBF was composed of dense, interconnecting, three-dimensional lymphatic vessels. It was classified into three patterns according to the composition of the lymphatic vessels: a linear structure of lymphatic collectors (pattern 1), a network of lymphatic capillaries and lymphatic collectors in an underlying layer (pattern 2), and lymphatic capillaries and precollectors with no lymphatic collectors (pattern 3). Conclusions PAL showed the structure of DBF more precisely than ICG fluorescence lymphography. The use of PAL to visualize DBF assists in understanding the pathophysiology and assessing the severity of cancer-related lymphedema.

Background Lymphaticovenular anastomosis (LVA) is a minimally invasive surgical procedure used to treat lymphedema. Volumetric measurements and quality-of-life assessments are often performed to assess the effectiveness of LVA, but there is no method that provides information regarding postoperative morphological changes in lymphatic vessels and veins after LVA. Photoacoustic lymphangiography (PAL) is an optical imaging technique that visualizes the distribution of light-absorbing molecules, such as hemoglobin or indocyanine green (ICG), and provides three-dimensional images of superficial lymphatic vessels and the venous system simultaneously. In this study, we performed PAL in lymphedema patients before and after LVA and compared the images to evaluate the effect of LVA. Methods PAL was performed using the PAI-05 system in three patients (one man, two women) with lymphedema, including one primary case and two secondary cases, before LVA. ICG fluorescence lymphography was performed in all cases before PAL. Follow-up PAL was performed between 5 days and 5 months after LVA. Results PAL enabled the simultaneous visualization of clear lymphatic vessels that could not be accurately seen with ICG fluorescence lymphography and veins. We were also able to observe and analyze morphological changes such as the width and the number of lymphatic vessels and veins during the follow-up PAL after LVA. Conclusions By comparing preoperative and postoperative PAL images, it was possible to analyze the morphological changes in lymphatic vessels and veins that occurred after LVA. Our study suggests that PAL would be useful when assessing the effect of LVA surgery.

Recent reports have described several cases of double muscle transfers to restore natural, symmetrical smiles in patients with long-standing facial paralysis. However, these complex procedures sometimes result in cheek bulkiness owing to the double muscle transfer. We present the case of a 67-year-old woman with long-standing facial paralysis, who underwent two-stage facial reanimation using two superficial subslips of the serratus anterior muscle innervated by the masseteric and contralateral facial nerves via a sural nerve graft. Each muscle subslip was transferred to the upper lip and oral commissures, which were oriented in different directions. Furthermore, a horizontal fascia lata graft was added at the lower lip to prevent deformities such as lower lip elongation and deviation. Voluntary contraction was noted at roughly 4 months, and a spontaneous smile without biting was noted 8 months postoperatively. At 18 months after surgery, the patient demonstrated a spontaneous symmetrical smile with adequate excursion of the lower lip, upper lip, and oral commissure, without cheek bulkiness. Dual-innervated muscle transfer using two multivector superficial subslips of the serratus anterior muscle may be a good option for long-standing facial paralysis, as it can achieve a symmetrical smile that can be performed voluntarily and spontaneously.

Complex physical therapy (CPT), which combines compression and exercise therapies, is the cornerstone of lymphedema treatment. However, assessing lymphatic flow in living humans is challenging owing to the small size and transparent nature of lymphatic vessels. Herein, we introduce a novel approach utilising photoacoustic imaging (PAI) to visualise lymphatic flow dynamics under CPT conditions. Compared with existing modalities, PAI offers superior details, enabling real-time evaluation of lymphatic vessels during compression and exercise. Real-time evaluation of lymphatic flow may enable advanced research on optimal perioperative compression therapy and exercise therapy. Herein, PAI was used to assess lymphatic flow in four healthy subjects. Detailed images of lymphatic and blood vessels were obtained using photoacoustic lymphangiography, which utilises indocyanine green as a light absorber. The participants underwent simulated compression using a transparent film dressing, with a pressure of approximately 20 mmHg. Exercise stress was applied to mimic CPT conditions. Compression facilitated the collapse of superficial veins while lymphatic vessels remained intact. Additionally, the lymphatic pumping frequency was the highest during combined compression and exercise, highlighting the synergistic effect of these therapies on lymphatic flow. Our findings underscore the potential of PAI in elucidating the mechanisms underlying the efficacy of CPT. PAI may enable comprehensive assessments of vascular changes during CPT by allowing simultaneous delineation of veins and lymphatic vessels. While our study represents a significant step forward, its limitations, including small sample size and exercise regimen specificity, warrant further investigations.