The Upper Extremity Lymphatic System Is Not Symmetrical in Individuals: An Anatomic Study Utilizing ICG Lymphography and SPECT/CT Lymphoscintigraphy.

OBJECTIVE: We evaluated whether superficial lymphatic anatomy and functional lymph node drainage are symmetric between the right and left upper extremities of healthy female volunteers, and if handedness is associated with symmetry of superficial lymphatic anatomy. BACKGROUND: Symmetry of lymphatic anatomy has been assumed historically. This assumption of individual anatomic symmetry is being utilized clinically and in research without validation. METHODS: 36 normal female volunteers underwent bilateral indocyanine green (ICG) lymphography and lymphoscintigraphy of the upper extremities. Eight collecting vessel pathways of each upper extremity were mapped on ICG lymphography. 13 lymph node groups were visualized on lymphoscintigraphy. Symmetry of lymphatic anatomy and functional drainage were established by comparing the right and left extremities of each participant. Hand dominance was assessed by hand grip strength on a hand dynamometer. RESULTS: Among the 36 participants, 10 (28%) showed symmetry of all eight upper extremity lymphatic pathways with ICG. However, only 1 (3%) participant demonstrated complete symmetry amongst the 13 lymph node groups. Total symmetry of lymphatic channels was observed on ICG in seven (39%) participants with hand dominance and three (17%) participants without hand dominance (X2 = 2.215, P = 0.137). CONCLUSION: Lymphatic anatomy and functional drainage of the upper extremities are not consistently symmetric. Functional nodal drainage as demonstrated by lymphoscintigraphy shows less symmetry than anatomic studies of lymphatic channels using ICG. Symmetric lymphatic anatomy does not appear to correlate with hand dominance. These findings challenge the prevailing assumption of left-right lymphatic symmetry.

Noncontrast Ultra-High-Frequency Ultrasound for Preoperative Lymphovenous Mapping in Patients Undergoing Lymphaticovenous Anastomosis Surgery for Extremity Lymphedema.

Among 25 patients with extremity lymphedema who underwent noncontrast ultra-high-frequency ultrasound (UHFUS) for preoperative lymphovenous mapping before lymphaticovenous anastomosis (LVA) surgery, the LVA success rate by lymphovenous pair was 96.7% and by patient was 96.0%. UHFUS exhibited high agreement with surgical measurements for lymphatic channel and vein diameters.

A Cost-Utility Analysis of the Use of -125 mm Hg Closed-incision Negative Pressure Therapy in Oncoplastic Breast Surgery.

Background: Closed-incision negative pressure therapy (ciNPT) decreases the rate of wound complications in oncoplastic breast surgery (OBS) but at a fiscal cost. Our aim was to examine the cost-utility of ciNPT in OBS. Methods: A literature review was performed to obtain the probabilities and outcomes for the treatment of unilateral breast cancer with OBS with ciNPT versus without. Reported utility scores in the literature were used to calculate quality-adjusted life years (QALYs) for each health state. A decision analysis tree was constructed with rollback analysis to determine the more cost-effective strategy. An incremental cost-utility ratio was calculated. Sensitivity analyses were performed. Results: OBS with ciNPT is associated with a higher clinical effectiveness (QALY) of 33.43 compared to without (33.42), and relative cost increase of $667.89. The resulting incremental cost-utility ratio of $57432.93/QALY favored ciNPT. In one-way sensitivity analysis, ciNPT was the more cost-effective strategy if the cost of ciNPT was less than $1347.02 or if the probability of wound dehiscence without was greater than 8.2%. Monte Carlo analysis showed a confidence of 75.39% that surgery with ciNPT is more cost effective. Conclusion: Despite the added cost, surgery with ciNPT is cost-effective. This finding is a direct result of decreased overall wound complications with ciNPT.

Collateralization of the upper extremity lymphatic system after axillary lymph node dissection.

BACKGROUND: Lymphatic drainage from the arm may be altered after axillary lymph node dissection (ALND). Understanding these alterations is important as they may change standard surgical and radiation treatment in recurrent breast cancer or upper extremity skin cancers, including melanoma. METHODS: Utilizing a single-institution planar and single photon emission computed tomography/computed tomography lymphoscintigraphy database, we identified patients with a diagnosis of upper extremity cutaneous melanoma from 2008 to 2023 who previously underwent ALND for cancer treatment and did not develop upper extremity cancer-related lymphedema. ALND patients were matched to control patients presenting with cutaneous melanomas at the same anatomic sites. Sentinel lymph nodes (SLNs) were compared between both groups. RESULTS: Of 3628 upper extremity melanoma cutaneous patients, 934 met inclusion criteria, including 22 ALND and 912 control patients. Level I axillary SLN drainage was observed in 98% of controls and 27% of ALND patients (p < 0.001). Level II axillary SLN drainage was observed in 3% of controls and 27% of ALND patients (p < 0.001). Level III axillary SLN drainage was observed in 1% of controls and 32% of ALND patients (p < 0.001). Epitrochlear SLN drainage was observed in 9% of controls and 32% of ALND patients, respectively (p < 0.046). Brachial SLN drainage was observed in 4% of controls and 23% of ALND patients (p < 0.001). CONCLUSIONS: Distinct changes in functional lymphatic drainage were seen between the arms of patients who previously underwent ALND versus control patients. Levels II and III axillary, epitrochlear, and brachial nodes are possible sites of metastatic disease that should be considered in patients with a prior ALND.

Patterns of forearm lymphatic drainage to the epitrochlear lymph nodes in 1400 cutaneous melanoma patients.

BACKGROUND: Variations of hand and forearm lymphatic drainage to upper-arm lymphatic pathways may impact the route of melanoma metastasis. This study compared rates of lymphatic drainage to epitrochlear nodes between anatomic divisions of the hand and forearm to determine whether the anatomic distribution of hand and forearm melanomas affects the likelihood of drainage to epitrochlear lymph nodes. METHODS: Using a single-institution lymphoscintigraphy database, we identified all patients with cutaneous melanoma on the hand and forearm. A body-map two-dimensional coordinate system was used to classify cutaneous melanoma sites between radial-ulnar and dorsal-volar divisions. Sentinel lymph nodes (SLNs) visualized on lymphoscintigraphy were recorded. Proportions of patients with epitrochlear SLNs were compared between anatomic divisions using χ2 analysis. RESULTS: Of 3628 upper extremity cutaneous melanoma patients who underwent lymphatic mapping with lymphoscintigraphy, 1400 met inclusion criteria. Twenty-one percent of patients demonstrated epitrochlear SLNs. Epitrochlear SLNs were observed in 27% of dorsal forearm melanomas and 15% of volar forearm melanomas (p < 0.001). Epitrochlear SLNs were observed in 31% of ulnar forearm melanomas and 17% of radial forearm melanomas (p < 0.001). CONCLUSIONS: Higher proportions of dorsal and ulnar forearm melanomas have epitrochlear SLNs. Metastasis to epitrochlear SLNs may be more likely from melanomas in these respective forearm regions.

Changes on noncontrast magnetic resonance imaging following lymphatic surgery for upper extremity secondary lymphedema.

OBJECTIVE: To assess changes in noncontrast magnetic resonance imaging (MRI)-based biomarkers after upper extremity lymphedema surgery. METHODS: We retrospectively identified secondary upper extremity lymphedema patients who underwent vascularized lymph node transplant (VLNT), debulking lipectomy, or VLNT with a prior debulking (performed separately). All patients with both preoperative and postoperative MRIs were compared. An MRI-based edema scoring system was used: 0 (no edema), 1 (<50% fluid from myofascial to dermis), and 2 (≥50% fluid from myofascial to dermis). Edema scores and subcutaneous thickness (ST) were obtained along four quadrants across the upper and lower third of the arm and forearm each-for a total of 16 anatomical locations-and compared before and after surgery. Net changes in edema scores and ST were then correlated with Lymphoedema Quality-of-Life Questionnaire scores, L-Dex (bioimpedance), and limb volume difference by perometry. RESULTS: Patients who underwent lymphatic surgeries between January 2017 and December 2022 and successfully completed preoperative and postoperative MRI were included, resulting in a total of 33 unilateral secondary upper extremity lymphedema patients m(mean age, 63 ± 14 years; 32 female). The median postoperative follow-up times were 12.5 months (range, 6-19 months) for VLNT, 13.5 months (range, 12-40 months) for debulking, and 12.0 months (range, 12-24 months) for patients who underwent VLNT after debulking surgery. There was a decrease in mean ST in 15 of 16 anatomical segments of the upper extremity after debulking (P < .001), and the edema score increased in 7 of 16 segments (P ≤ .001-.020). Edema stage did not change in patients who underwent VLNT only or VLNT after debulking. ST decreased only along the radial forearm in patients who underwent VLNT after debulking despite an improvement in the Lymphoedema Quality-of-Life Questionnaire score in the former group. There was correlation between a decrease in ST with a decrease in volume within the debulking group (r = 0.79; P < .001). A decrease in ST also correlated with improved lymphedema quality of life questionnaires in the debulking group (r = 0.49; P = .04). CONCLUSIONS: A decrease in ST was demonstrated in most anatomical segments after liposuction debulking, whereas edema stage was increased. Fewer changes were seen with VLNT, possibly a reflection of more gradual changes within this short follow-up period, with the radial forearm potentially revealing the earliest response.

A Multiresolution Approach with Method-Informed Statistical Analysis for Quantifying Lymphatic Pumping Dynamics.

Despite significant strides in lymphatic system imaging, the timely diagnosis of lymphatic disorders remains elusive. One main cause for this is the absence of standardized, quantitative methods for real-time analysis of lymphatic contractility. Here, we address this unmet need by combining near-infrared lymphangiography imaging with an innovative analytical workflow. We combined data acquisition, signal processing, and statistical analysis to integrate traditional peak and-valley with advanced wavelet time-frequency analyses. Decision theory was used to evaluate the primary drivers of attributable variance in lymphangiography measurements to generate a strategy for optimizing the number of repeat measurements needed per subject to increase measurement reliability. This approach not only offers detailed insights into lymphatic pumping behaviors across species, sex and age, but also significantly boosts the reliability of these measurements by incorporating multiple regions of interest and evaluating the lymphatic system under various gravitational loads. By addressing the critical need for improved imaging and quantification methods, our study offers a new standard approach for the imaging and analysis of lymphatic function that can improve our understanding, diagnosis, and treatment of lymphatic diseases. The results highlight the importance of comprehensive data acquisition strategies to fully capture the dynamic behavior of the lymphatic system.

Optimizing Surgical Outcomes and the Role of Preventive Surgery: A Scoping Review.

BACKGROUND: Plastic and reconstructive surgeons are often presented with reconstructive challenges as a sequela of complications in high-risk surgical patients, ranging from exposure of hardware, lymphedema, and chronic pain after amputation. These complications can result in significant morbidity, recovery time, resource utilization, and cost. Given the prevalence of surgical complications managed by plastic and reconstructive surgeons, developing novel preventative techniques to mitigate surgical risk is paramount. METHODS: Herein, we aim to understand efforts supporting the nascent field of Preventive Surgery, including (1) enhanced risk stratification, (2) advancements in postoperative care. Through an emphasis on four surgical cohorts who may benefit from preventive surgery, two of which are at high risk of morbidity from wound-related complications (patients undergoing sternotomy and spine procedures) and two at high risk of other morbidities, including lymphedema and neuropathic pain, we aim to provide a comprehensive and improved understanding of preventive surgery. Additionally, the role of risk analysis for these procedures and the relationship between microsurgery and prophylaxis is emphasized. RESULTS: (1) medical optimization and prehabilitation, (2) surgical mitigation techniques. CONCLUSION: Reconstructive surgeons are ideally placed to lead efforts in the creation and validation of accurate risk assessment tools and to support algorithmic approaches to surgical risk mitigation. Through a paradigm shift, including universal promotion of the concept of "Preventive Surgery," major improvements in surgical outcomes may be achieved.

Immediate lymphatic reconstruction: Lessons learned over eight years.

Immediate lymphatic reconstruction (ILR) is recognized as a surgical approach used to reduce the risk of developing secondary lymphedema, and evidence demonstrating the efficacy of ILR is favorable. Our Lymphatic Center has become a centralized location offering ILR for the risk-reduction in breast cancer-related lymphedema (BCRL) in New England. Over the course of our experience, we made several modifications and adapted our approach to enhance the operative success of this procedure. These include advancements in our use of indocyanine green (ICG) imaging to identify baseline lymphatic anatomical variation, utilization of fluorescein isothiocyanate for lymphatic vessel visualization, application of the lymphosome concept to guide arm injection sites, verification of anastomotic patency (using ICG), localization of reconstruction to guide radiation therapy, incorporation of intraoperative tools to facilitate better anatomic visualization of the axilla, and addition of a lower extremity vein graft to mitigate venous-related complications. Collecting information from each surgery in a standardized manner, including intraoperative lymphatic channel measurements, and deploying clips for possible future radiation exposure, enables future studies on ILR patient outcomes. In this contribution, we aimed to share our institutional modifications with the surgical community to facilitate further adoption, conversation, and advancement of ILR for the risk-reduction in BCRL.

Development of "Explore Plastic Surgery": An Educational Program for Medical Students Without Home Residency Programs.

BACKGROUND: Medical students who attend institutions without plastic surgery residency programs are at a disadvantage in the plastic surgery match. We developed an educational program for medical students without home programs called Explore Plastic Surgery to provide an overview of the steps toward a career in plastic surgery. The purpose of this study was to assess the impact, utility, and success of the novel program. METHODS: Pre- and postevent surveys were distributed to participants. Survey data were analyzed including participant demographics, perceptions of barriers unique to those without home programs, and the overall event utility. RESULTS: Two hundred seventeen students registered for the program. Ninety-five participants completed the pre-event survey (44%), and of those, 57 participants completed the post-event survey (60%). There was an increase in understanding of the steps toward a career in plastic surgery ( P < 0.001), confidence in overcoming barriers ( P = 0.005), and level of comfort in reaching out to faculty for opportunities ( P = 0.01). There was a decrease in the perceived negative impact that attending medical schools without a home program will have on their abilities to pursue careers in plastic surgery ( P = 0.006). CONCLUSIONS: After the event, participants demonstrated an increase in their confidence in overcoming barriers and a decrease in their perceptions that attending an institution without a home program would negatively impact their ability to pursue plastic surgery. Initiatives focused on early exposure and recruitment of medical students may be important to promote accessibility and diversity within plastic surgery.

Mapping the Anatomy of the Human Lymphatic System.

BACKGROUND: While substantial anatomical study has been pursued throughout the human body, anatomical study of the human lymphatic system remains in its infancy. For microsurgeons specializing in lymphatic surgery, a better command of lymphatic anatomy is needed to further our ability to offer surgical interventions with precision. In an effort to facilitate the dissemination and advancement of human lymphatic anatomy knowledge, our teams worked together to create a map. The aim of this paper is to present our experience in mapping the anatomy of the human lymphatic system. METHODS: Three steps were followed to develop a modern map of the human lymphatic system: (1) identifying our source material, which was "Anatomy of the human lymphatic system," published by Rouvière and Tobias (1938), (2) choosing a modern platform, the Miro Mind Map software, to integrate the source material, and (3) transitioning our modern platform into The Human BioMolecular Atlas Program (HuBMAP). RESULTS: The map of lymphatic anatomy based on the Rouvière textbook contained over 900 data points. Specifically, the map contained 404 channels, pathways, or trunks and 309 lymph node groups. Additionally, lymphatic drainage from 165 distinct anatomical regions were identified and integrated into the map. The map is being integrated into HuBMAP by creating a standard data format called an Anatomical Structures, Cell Types, plus Biomarkers table for the lymphatic vasculature, which is currently in the process of construction. CONCLUSION: Through a collaborative effort, we have developed a unified and centralized source for lymphatic anatomy knowledge available to the entire scientific community. We believe this resource will ultimately advance our knowledge of human lymphatic anatomy while simultaneously highlighting gaps for future research. Advancements in lymphatic anatomy knowledge will be critical for lymphatic surgeons to further refine surgical indications and operative approaches.

Piezo1 regulates meningeal lymphatic vessel drainage and alleviates excessive CSF accumulation.

Piezo1 regulates multiple aspects of the vascular system by converting mechanical signals generated by fluid flow into biological processes. Here, we find that Piezo1 is necessary for the proper development and function of meningeal lymphatic vessels and that activating Piezo1 through transgenic overexpression or treatment with the chemical agonist Yoda1 is sufficient to increase cerebrospinal fluid (CSF) outflow by improving lymphatic absorption and transport. The abnormal accumulation of CSF, which often leads to hydrocephalus and ventriculomegaly, currently lacks effective treatments. We discovered that meningeal lymphatics in mouse models of Down syndrome were incompletely developed and abnormally formed. Selective overexpression of Piezo1 in lymphatics or systemic administration of Yoda1 in mice with hydrocephalus or Down syndrome resulted in a notable decrease in pathological CSF accumulation, ventricular enlargement and other associated disease symptoms. Together, our study highlights the importance of Piezo1-mediated lymphatic mechanotransduction in maintaining brain fluid drainage and identifies Piezo1 as a promising therapeutic target for treating excessive CSF accumulation and ventricular enlargement.

Advances in lymphedema: An under-recognized disease with a hopeful future for patients.

Lymphedema has traditionally been underappreciated by the healthcare community. Understanding of the underlying pathophysiology and treatments beyond compression have been limited until recently. Increased investigation has demonstrated the key role of inflammation and resultant fibrosis and adipose deposition leading to the clinical sequelae and associated reduction in quality of life with lymphedema. New imaging techniques including magnetic resonance imaging (MRI), indocyanine green lymphography, and high-frequency ultrasound offer improved resolution and understanding of lymphatic anatomy and flow. Nonsurgical therapy with compression, exercise, and weight loss remains the mainstay of therapy, but growing surgical options show promise. Physiologic procedures (lymphovenous anastomosis and vascularized lymph node transfers) improve lymphatic flow in the diseased limb and may reduce edema and the burden of compression. Debulking, primarily with liposuction to remove the adipose deposition that has accumulated, results in a dramatic decrease in limb girth in appropriately selected patients. Though early, there are also exciting developments of potential therapeutic targets tackling the underlying drivers of the disease. Multidisciplinary teams have developed to offer the full breadth of evaluation and current management, but the development of a greater understanding and availability of therapies is needed to ensure patients with lymphedema have greater opportunity for optimal care.

Expanding Access to Immediate Lymphatic Reconstruction Through an Axillary Surgery Referral Program: A 6-Year Single-Center Experience.

BACKGROUND: Recent advances in breast cancer have progressed toward less aggressive axillary surgery. However, axillary lymph node dissection (ALND) remains necessary in specific cases and can increase the risk of lymphedema. Performing ALND with immediate lymphatic reconstruction (ILR) can help lower this risk. This report outlines the implementation of an Axillary Surgery Referral Program (ASRP) to broaden access to ILR, providing insights for institutions considering similar initiatives. METHODS: A retrospective study analyzed patients referred to the ASRP at Beth Israel Deaconess Medical Center (BIDMC) between 6 January 2017 and 10 December 2022. Patients were identified from a prospective registry, with data subsequently extracted from electronic medical records. This analysis specifically centered on patients referred from external institutions to undergo ALND with ILR. RESULTS: The program received referrals for 131 patients from institutions across five different states. Annual referrals steadily increased over time. The primary indication for referral was residual axillary disease after neoadjuvant chemotherapy (41.2%). Among the referrals, 20 patients (15.3%) no longer required ALND due to axillary pathologic complete response to neoadjuvant therapy. Care coordination played a crucial role in streamlining the patient care process for both efficiency and effectiveness. CONCLUSION: The ASRP expands access to ILR for patients with breast cancer, the majority referred for surgical management of residual disease after chemotherapy. The program provides a model for health care institutions aiming to establish similar specialized referral services. Continued program evaluation will be instrumental in refining axillary surgery referral practices and ensuring optimal patient care.

Evaluation of Primary Lymphedema with Intranodal Lymphangiography.

PURPOSE: There are limited existing data on the lymphatic anatomy of patients with primary lymphedema (LED), which is caused by aberrant development of lymphatic channels. In addition, there is a paucity of contemporary studies that use groin intranodal lymphangiography (IL) to evaluate LED anatomy. The purpose of this retrospective observational study was to better delineate the disease process and anatomy of primary LED using groin IL. MATERIALS AND METHODS: We identified common groin IL findings in a cohort of 17 primary LED patients performed between 1/1/2017 and 1/31/2022 at a single institution. These patients were clinically determined to have primary lymphedema and demonstrated associated findings on lower extremity MR and lymphoscintigraphy. RESULTS: Ten patients (59%) demonstrated irregular lymph node morphology or a paucity of lymph nodes on the more symptomatic laterality. Eight patients (47%) demonstrated lymphovenous shunting from pre-existing anastomoses between the lymphatic and venous systems. Eight patients (47%) demonstrated passage of contrast past midline to the contralateral lymphatics. Finally, 12 patients (71%) failed to opacify the cisterna chyli and thoracic duct on their initial lymphangiograms. Delayed computed tomography of 3 patients showed eventual central lymphatic opacification up to the renal veins, but none of these patients showed central lymphatic opacification to the thorax. CONCLUSION: This descriptive, exploratory study demonstrates common central groin IL findings in primary LED to highlight patterns interventional radiologists should identify and report when addressing primary LED.

Edematous Dermal Thickening on Magnetic Resonance Imaging as a Biomarker for Lymphatic Surgical Outcomes.

Background and Objectives: One of the surgical treatments for breast cancer-related lymphedema (BCRL) is debulking lipectomy. The aim of this study is to investigate whether dermal thickness could be utilized as an objective indicator of post-operative changes following debulking. Materials and Methods: A retrospective review of BCRL patients who underwent debulking lipectomy was conducted. MRI-based dermal thickness was measured by two separate trained readers at 16 regions of the upper extremity. Pre- and post-operative reduction in dermal thickness was compared across the affected and unaffected (control) arms for each patient. The Wilcoxon rank sum test was used to assess for significant change. Univariate linear regression was used to assess the relationship between dermal thickness reduction and changes to LYMPH-Q scores, L-Dex scores, and relative volume change. Results: Seventeen patients were included in our analysis. There was significant reduction in dermal thickness at 5/16 regions in the affected arm. Dermal thickness change was significantly correlated with LYMPH-Q scores, L-Dex scores, and relative volume change in 2/16 limb compartments. There was predominant dermal thickening in the dorsal compartment of the upper arm and in the ventral and ulnar compartments of the forearm. Conclusions: Dermal thickness shows promising utility in tracking post-operative debulking procedures for breast cancer-related lymphedema. Further studies with larger patient populations and a variety of imaging modalities are required to continue to develop a clinically objective and reproducible method of post-surgical lymphedema staging and monitoring.

Fluid Distribution Patterns in Early-Stage Upper Extremity Lymphedema.

INTRODUCTION: Magnetic resonance imaging (MRI) stage 1 (early stage) upper extremity lymphedema is characterized by fluid infiltration in the subcutaneous tissues that does not exceed 50% of the extremity circumference at any level. The spatial fluid distribution in these cases has not been detailed and may be important to help determine the presence and location of compensatory lymphatic channels. The aim of this study is to determine whether there was a pattern of distribution of fluid infiltration in patients with early-stage lymphedema that could correspond to known lymphatic pathways in the upper extremity. METHODS: A retrospective review identified all patients with MRI stage 1 upper extremity lymphedema who were evaluated at a single lymphatic center. Using a standardized scoring system, a radiologist graded the severity of fluid infiltration at 18 anatomical locations. A cumulative spatial histogram was then created to map out regions where fluid accumulation occurred most and least frequently. RESULTS: Eleven patients with MRI stage 1 upper extremity lymphedema were identified between January 2017 and January 2022. The mean age was 58 years and the mean BMI was 30 m/kg2. One patient had primary lymphedema and the remaining 10 had secondary lymphedema. The forearm was affected in nine cases, and fluid infiltration was predominantly concentrated along the ulnar aspect, followed by the volar aspect, while the radial aspect was completely spared. Within the upper arm, fluid was primarily concentrated distally and posteriorly, and occasionally medially. CONCLUSIONS: In patients with early-stage lymphedema, fluid infiltration is concentrated along the ulnar forearm and the posterior distal upper arm, which aligns with the tricipital lymphatic pathway. There is also sparing of fluid accumulation along the radial forearm in these patients, suggesting a more robust lymphatic drainage along this region, possibly due to a connection to the lateral upper arm pathway.

Non-Linear Lymphatic Anatomy in Breast Cancer Patients Prior to Axillary Lymph Node Dissection: A Risk Factor For Lymphedema Development.

Immediate lymphatic reconstruction (ILR) at the time of axillary lymph node dissection (ALND) has become increasingly utilized for the prevention of breast cancer related lymphedema. Preoperative indocyanine green (ICG) lymphography is routinely performed prior to an ILR procedure to characterize baseline lymphatic anatomy of the upper extremity. While most patients have linear lymphatic channels visualized on ICG, representing a non-diseased state, some patients demonstrate non-linear patterns. This study aims to determine potential inciting factors that help explain why some patients have non-linear patterns, and what these patterns represent regarding the relative risk of developing postoperative breast cancer related lymphedema in this population. A retrospective review was conducted to identify breast cancer patients who underwent successful ILR with preoperative ICG at our institution from November 2017-June 2022. Among the 248 patients who were identified, 13 (5%) had preoperative non-linear lymphatic anatomy. A history of trauma or surgery of the affected limb and an increasing number of sentinel lymph nodes removed prior to ALND appeared to be risk factors for non-linear lymphatic anatomy. Furthermore, non-linear anatomy in the limb of interest was associated with an increased risk of postoperative lymphedema development. Overall, non-linear lymphatic anatomy on pre-operative ICG lymphography appears to be a risk factor for developing ipsilateral breast cancer-related lymphedema. Guided by the study's findings, when breast cancer patients present with baseline non-linear lymphatic anatomy, our institution has implemented a protocol of prophylactically prescribing compression sleeves immediately following ALND.