Electrophysiological Signal Validation of Regenerative Peripheral Nerve Interface (RPNI) at Nerve Ending: A Preliminary Rat Model Experiment.

Background As the number of extremity amputations continues to rise, so does the demand for prosthetics. Emphasizing the importance of a nerve interface that effectively amplifies and transmits physiological signals through peripheral nerve surgery is crucial for achieving intuitive control. The Regenerative Peripheral Nerve Interface (RPNI) is recognized for its potential to provide this technical support. Through animal experiment, we aimed to confirm the actual occurrence of signal amplification. Methods Rats were divided into three experimental groups: control, common peroneal nerve transection, and RPNI groups. Nerve surgeries were performed for each group, and electromyography (EMG) and nerve conduction studies (NCS) were conducted at the initial surgery, as well as at two, four and eight weeks postoperatively. Results All implemented RPNIs exhibited viability and displayed adequate vascularity with the proper color. Clear differences in latency and amplitude were observed before and after eight weeks of surgery in all groups (p < 0.05). Notably, the RPNI group demonstrated a significantly increased amplitude compared to the control group after eight weeks (p = 0.031). Latency increased in all groups eight weeks after surgery. The RPNI group exhibited relatively clear signs of denervation with abnormal spontaneous activities (ASA) during EMG. Conclusions This study is one of few preclinical studies that demonstrating the electrophysiological effects of RPNI and validating the neural signals. It serves as a foundational step for future research in human-machine interaction and nerve interfaces.

The Possible Role of Lymphaticovenous and Lymph Node to Vein Anastomosis for Improvement of Milroy Disease Related Congenital Chylothorax and Lower Extremity Lymphedema.

INTRODUCTION: Primary lymphedema is characterized by lymphatic dysplasia in which one variant is Milroy's disease. The association with congenital chylothorax is even rarer with poor outcome. This is the first report to utilize peripheral lymphovenous anastomosis (LVA) and lymph node to vein anastomosis (LNVA) for the management of such condition. METHODS: Retrospective chart review of patients with Milroy's disease with complication of chylothorax between 2019 till 2023 was performed. Clinical assessment and radiological investigations were reviewed. RESULTS: Six patients with mean age of 12±3.9 years and disease duration of 10.5±2.8 years were reviewed. Three had ISL stage 3 while others had stage 2 late disease. All had bilateral lower extremity lymphedema and chylothorax with history of chest tube drainage. After LVA and LNVA, significant reduction in extremity volume was noted (p=0.028) along with near complete resolution of chylothorax was noted during the long-term follow-up (32 ±17.9 months). CONCLUSION: Milroy's disease complicated with chylothorax remains to be challenging. This is the first report utilizing peripheral bypass (LVA and LNVA) which resulted in improvement of both lower extremity lymphedema and chylothorax. The utility of this approach represents a promising modality in the management of this devastating condition.

Does Lymphovenous Anastomosis Effect Mammalian Target of Rapamycin Inhibitor-associated Lymphedema Patients?

The mammalian target of rapamycin (mTOR) inhibitors are used to prevent organ transplant rejection and are preferred over other immunosuppressants due to its low nephrotoxicity. However, mTOR inhibitors have been associated with various adverse effects including lymphedema. Although rare in incidence, previously known treatments for mTOR inhibitor-induced lymphedema were limited to discontinuation of related drugs and complex disruptive therapy with variable results. In this article, three patients who developed lymphedema in their lower limbs after using mTOR inhibitors, including two bilateral and one unilateral case, were treated with physiologic surgery methods such as lymphovenous anastomosis (LVA) and lymph node transfer. The efficacy of the treatment was evaluated. In the three cases described, cessation of the drug did not lead to any reduction in edema. The use of LVA and lymph node transfer resulted in early reductions in volume but failed to sustain over time. All patients underwent secondary nonphysiologic surgery such as liposuction resulting in sustained improvement. This series presents the first physiologic approach to mTOR inhibitor-induced lymphedema. Although further study is warranted, the physiologic surgical options may have limited success and nonphysiologic options may offer better sustainable results.

Lipedema associated with Skin Hypoperfusion and Ulceration: Soft Tissue Debulking Improving Skin Perfusion.

Lipedema is a progressive connective tissue disease with enlargement of adipose tissue, fibrosis, fluid collection, and dermal thickening. Herein, we present a case of lipedema associated with skin hypoperfusion and ulceration in which soft tissue debulking with liposuction improved patients' symptoms. A 39-year-old female presented with asymmetric progressive initially unilateral lower limb swelling with severe pain with subsequent skin ulceration. Conservative management failed to improve her condition. After excluding other causes and detailed radiologic investigation, lipedema was diagnosed with an associated impaired skin perfusion. Trial of local wound care and compression therapy failed to improve the condition. Subsequent soft tissue debulking with circumferential liposuction and ulcer debridement and immediate compression showed dramatic improvement of the symptoms and skin perfusion. The unique nature of this case sheds light on lipedema as a loose connective tissue disease. Inflammation and microangiopathies explain the associated pain with hypoperfusion and ulceration being quite atypical and in part might be related to the large buildups of matrix proteins and sodium contents leading to fragility in microvessels with frequent petechiae and hematoma and subsequent tissue ischemia. Conservative measures like compression therapy plays a significant role in disease course. Surgical debulking with liposuction was shown to be efficacious in reducing the soft tissue load with improvement in limb pain, edema, circumference, and skin perfusion that was seen in our patient. Lipedema is a frequently misdiagnosed condition with disabling features. Skin involvement in lipedema with potential hypoperfusion was shown and it requires further investigation.

How to Start and Build Microsurgery Practice-Topics on Success and Sustainability: Global/International.

Many young microsurgeons begin their careers at established hospitals where microsurgery resources are limited. This article shares the authors' experiences in overcoming challenges and establishing a microsurgery practice in a new hospital. Due to the lack of equipment, limited support from colleagues, absence of discussion partners, fear of failure, and unpredictable situations, many aspiring microsurgeons lose their motivation. The purpose of this article is to guide future microsurgeons by describing the author's actions and suggesting improvements for their first free flap case. Key factors for building a successful, sustainable, and enjoyable microsurgery practice include remembering your training and mentors, acquiring fundamental knowledge of microsurgery, creating a supportive ecosystem, and having fun.

Identifying Functional Lymph Nodes in Lower Extremity Lymphedema Patients: The Role of High-frequency Ultrasound.

BACKGROUND: Lymph nodes may play a potential role in lymphedema surgery. Radiologic evaluation of nodes may reveal the status of pathologic conditions but with limited accuracy. This study is the first to evaluate the efficacy of ultrasound in detecting functioning nodes in lymphedema patients and presents a criterion for determining the functionality of the lymph nodes. METHODS: This retrospective study reviews 30 lower extremity lymphedema cases which were candidates for lymph node to vein anastomosis. Lymphoscintigraphy and magnetic resonant lymphangiography (MRL) imaging were compared with ultrasound features which were correlated to intraoperative indocyanine green (ICG) nodal uptake as an indication of functionality. RESULTS: Majority were International Society of Lymphology stage 2 late (50.0%) and stage 3 (26.7%). ICG positive uptake (functioning nodes) was noted in 22 (73.3%), while 8 patients (26.6%) had negative uptake (nonfunctioning). Ultrasound had significantly the highest specificity (100%) for identifying functional nodes followed by lymphoscintigraphy (55%) and MRL (36%; p = 0.002, p < 0.001, respectively). This was associated with 100% positive predictive value compared against lymphoscintigraphy (44%) and MRL (36%; p < 0.001 for both). The identified ultrasound imaging criteria for functioning lymph node were oval lymph node shape (Solbiati Index), morphology, vascularity pattern, and vascularity quantification. CONCLUSION: The use of ultrasound in nodal evaluation was proven effective in different pathologic conditions and demonstrated the best prediction for functionality of the lymph node based on the new evaluation criteria.

Effect of a portable light emitting diode device on wound healing in a rat model.

Light-emitting diode (LED) lights produce a variety of wavelengths that have demonstrable efficacy in therapeutic and aesthetic fields. However, a repetitive treatment regimen is required to produce treatment outcomes, which has created a need for portable LED devices. In this study, we aimed to develop a portable therapeutic LED device and investigate its healing effect on excisional wounds in a rat model. The 35 × 35 mm-sized LED device was used on a total of 30 rats with full-thickness wounds that were divided into two groups depending on radiation intensity (11.1 and 22.2 mW/cm2 group). LED irradiation was performed every 24 h for 30 min, over 14 days, in direct contact with the wound. Percentage wound closure was measured by photographic quantification and was assessed histologically using haematoxylin and eosin (H&E) and Masson's Trichrome staining, and immunohistochemistry for Vascular endothelial growth factor (VEGF) and CD31. Percentage wound closure was significantly higher in 22.2 mW/cm2 irradiated wounds than that in the control wounds on days 7 and 10. The area of collagen deposition was remarkably larger in 22.2 mW/cm2 irradiated wounds than that in the control, with more horizontally organized fibres. CD31 immunostaining confirmed a significant increase in the number of microvessels in 22.2 mW/cm2 irradiated wounds than that in the control wounds, although there was no difference in VEGF immunostaining. Our novel portable LED device accelerates wound healing in a rat model, raising the possibility that portable LED devices can combine convenience with accessibility to play an innovative role in wound dressing.

Comparative Study of Small Vessel (under 0.8 mm) Anastomosed Free Flap and Larger Vessel (over 0.8 mm) Anastomosed Free Flap; Does Supermicrosurgery Provide Sufficient Blood Flow to the Free Flap?

BACKGROUND: This study aimed to quantify the blood flow of free flaps and compare the blood flow of small vessel (<0.8 mm) and larger vessel (>0.8 mm) anastomosed free flaps. METHODS: This retrospective study included patients treated successfully with a perforator free flap in the lower extremity between June 2015 and March 2017. A color duplex ultrasound system measured the flow volume through the pedicle by analyzing the mean flow peak velocity, flow volume, and flow volume per 100 g of the flap. RESULTS: A total of 69 patients were enrolled in this study. There was no statistical difference in peak velocity between the small vessel anastomosed free flap (25.2 ± 5.6) and larger vessel anastomosed free flap (26.5 ± 5.4). Flow volume (6.8 ± 4.2 vs. 6.3 ± 3.6) and flow volume/100 g (3.6 ± 3.9 vs. 6.2 ± 6.9) also did not show significant differences. CONCLUSION: Small vessel (<0.8 mm) free flaps showed similar flow velocity and flow volume to larger vessel (>0.8 mm) anastomosed free flaps. Blood flow to the small vessel anastomosed free flap was sufficient despite its small vessel size.

The Quality of Life after Lymphaticovenous Anastomosis in 118 Lower Limb Lymphedema Patients.

Background This is a prospective study on 118 patients who underwent lymphaticovenous anastomosis (LVA) due to secondary lower limb lymphedema between January 2018 and October 2020 to evaluate patients' quality of life (QOL) using the Quality of Life Measure for Limb Lymphedema (LYMQoL) questionnaire. Methods The outcome measurement included the LYMQoL leg scoring system tool evaluating the function, appearance, symptom, mood, and overall outcome. In addition, correlation analysis was performed for three factors: based on International Society of Lymphology (ISL) stages, disease duration, and amount of volume reduction. Results The LYMQoL tool overall satisfaction score significantly increased at all intervals from 4.4 ± 0.2 preoperative to 6.5 ± 0.3 postoperative at 12 months ( p < 0.001). Significant findings were seen for each domain scores compared preoperatively and at 12 months: function score (18.6 ± 0.5 to 15.4 ± 0.6), appearance score (17.8 ± 0.5 to 16.0 ± 0.6), symptom score (11.8 ± 0.3 to 8.9 ± 0.4), and mood score (14.5 ± 0.4 to 11.4 ± 0.5; p < 0.05). The correlation analysis between improvement of the overall score and the ISL stage ( p = 0.610, correlation coefficient [ r ] = - 0.047), disease duration ( p = 0.659, r = - 0.041), and amount of limb volume reduction ( p = 0.454, r = - 0.070) showed no statistical significance. Conclusion The QOL of secondary lower limb lymphedema patients was significantly improved after LVA regardless of the severity of disease, duration of disease, and amount of volume reduction after LVA. Understanding the patient-reported outcome measurement will help the surgeons to manage and guide the expectations of the patients.

Further insight in selecting the ideal vein for lymphaticovenous anastomosis: utilizing the anatomy and Venturi effect of a small vein/venule draining into the main vein.

INTRODUCTION: The functional and dilated lymphatic vessel and veins with minimal backflow and pressure are considered ideal for lymphaticovenous anastomsosis (LVA). However, how to select the ideal vein remains to be determined. This study aims to provide further insight in selecting the ideal vein. MATERIAL AND METHODS: This is a retrospective study evaluating 166 limbs with lymphedema with a minimal follow-up period of 12 months. The surgical approach included side-to-end LVA where one group used a non-Venturi LVA and the other used a small branch draining into a major vein (Venturi LVA). Preoperative, postoperative 1, 3, 6, 12 months limb volume, circumference, reduction volume and ratio were evaluated. RESULTS: The postoperative volume reduction was significant for both groups when compared to their respective preoperative volume. When compared between the 2 groups, the Venturi LVA had a significantly higher reduction volume and ratio at postoperative 1 month (240.82±260.73 cm³ vs 364.27±364.08 cm³, 6.13±5.62% vs 8.77±6.64%; p<0.05) and at 3 months (289.19±291.42 cm³ vs 432.50±395.04cm³, 7.31 ± 6.39% vs 10.55 ± 6.88%; p<0.05) However, the reduction volume and ratio was not significant towards month 6 and 12. CONCLUSION: This study provides further insight in selecting the ideal vein for LVA. By using a small vein draining into the main vein, valves play a role in reducing backflow. Furthermore, the Venturi effect allows significantly enhanced drainage especially in the initial period after surgery. The effect slowly plateaus after few months ultimately having a similar outcome of reduction at 12 months.