Retroauricular lymph node flap: An anatomic and surgical feasibility study.

BACKGROUND: The study investigated the anatomy of the retroauricular lymph node (LN) flap and evaluate its surgical feasibility as a new donor site for a free LN flap in lymphedema surgery. METHODS: Twelve adult cadavers were examined. The course and perfusion of the anterior auricular artery (AAA) and the location and sizes of the retroauricular LNs were studied. RESULTS: The AAA was available in 87% and absent in 13% specimens. The AAA's origin had a mean vertical distance of 12.2 ± 6.9 mm and a mean horizontal distance of 19.1 ± 4.2 mm from the superior attachment of the ear. The mean diameter of the AAA was 0.8 ± 0.2 mm. The mean number of LN per region was 7.7 ± 2.3, with an average LN size of 4.1 ± 1.9 × 3.2 ± 1.7 mm. The LN were categorized into anterior (G1) and posterior (G2) groups, with a total of 59 and 10 LN, respectively. In a cluster analysis, three LN clusters could be detected across the anterior group (G1). CONCLUSIONS: The retroauricular LN flap is a delicate but feasible flap with reliable anatomy, containing a mean of 7.7 LNs.

Preservation of supraclavicular nerve while harvesting supraclavicular lymph node flap.

Lymph node transfer has recently become one of the popular techniques for surgical treatment of lymphedema. We aimed to evaluate postoperative donor site numbness and other complications in patients who underwent supraclavicular lymph node flap transfer to treat lymphedema with preservation of the supraclavicular nerve. From 2004 to 2020, 44 cases of supraclavicular lymph node flap were reviewed retrospectively. In the donor area, sensorial evaluation was clinically done with the postoperative controls. Among them 26 had no numbness at all, 13 had short-term numbness, two had numbness for > 1 year and three had numbness for > 2 years. We suggest that careful preservation of the supraclavicular nerve branches can avoid the major complication of numbness around the clavicle.

Summary of hands-on supermicrosurgery course and live surgeries at 8th world symposium for lymphedema surgery.

The hands-on supermicrosurgery course provided participants a valuable learning experience of in-depth practices of supermicrosurgical skills with experts. Seven live surgeries were successfully demonstrated at 8th World Symposium for Lymphedema Surgery. Variable donor sites for vascularized lymph node transfer were the submental, supraclavicular, groin, and omental; while the recipient sites included the wrist and axilla in upper limb; and popliteal and groin in the lower limb. The therapeutic and preventive lymphovenous anastomosis was also satisfactorily performed.

Non-contrast-enhanced magnetic resonance angiography of facial arteries for pre-operative evaluation of vascularized submental lymph node flaps.

BACKGROUND: The aim of this study was to compare non-contrast-enhanced 3D phase contrast magnetic resonance angiography (3D PC-MRA) and conventional intravenous administration of contrast media, i.e., contrast-enhanced MRA (CE-MRA), to evaluate the courses of facial arteries for the preparation of vascularized submental lymph node flap (VSLN flap) transfer. METHODS: The head and neck regions of 20 patients with limb lymphedema were imaged using a 3 T MRI scanner. To improve the evaluation of facial artery courses, MRA was fused with anatomical structures generated by high-resolution T1-weighted imaging. The diagnostic and image qualities of facial arteries for VSLN flap planning were independently rated by two radiologists. Interobserver agreement was evaluated using Cohen's kappa. Differences between 3D PC-MRA and CE-MRA in terms of the diagnostic quality of facial arteries were evaluated using McNemar's test. RESULTS: Cohen's kappa indicated fair to good interobserver agreement for the diagnostic and image qualities of the bilateral facial arteries. No significant difference in terms of the diagnostic quality of the left and right facial arteries between 3D PC-MRA and CE-MRA, respectively, was identified. CONCLUSIONS: Non-contrast 3D PC-MRA is a reliable method for the evaluation of facial artery courses prior to VSLN flap transfer and could serve as an alternative to CE-MRA for patients with renal insufficiency or severe adverse reactions to contrast media.

Alternative vascular constructs of lymph node flap transfer.

Vascularized lymph node transfer is a quite innovative physiological surgical procedure for the lymphedema treatment. Although is gaining more popularity due to its promising results, there are some concerns regarding difficult to harvest it and the potential risk of iatrogenic lymphedema. Here, we present alternative vascular constructs of lymph node flap for the treatment of lymphedema, which provide the benefits of a technically easier dissection and physiological reconstruction of the damaged lymphatics. Furthermore, we introduce a classification based on the flap vascular supply including six types of flaps and we provide the details of the surgical technique.

The vascularized groin lymph node flap (VGLN): Anatomical study and flap planning using multi-detector CT scanner. The golden triangle for flap harvesting.

INTRODUCTION: A growing number of surgeons perform lymph node transfers for the treatment of lymphedema. When harvesting a vascularized lymph node groin flap (VGLNF) one of the major concerns is the potential risk of iatrogenic lymphedema of the donor-site. This article helps understanding of the lymph node distribution of the groin in order to minimize this risk. MATERIALS AND METHODS: Fifty consecutive patients undergoing abdominal mapping by multi-detector CT scanner were included and 100 groins analyzed. The groin was divided in three zones (of which zone II is the safe zone) and lymph nodes were counted and mapped with their distances to anatomic landmarks. Further node units were plotted and counted. RESULTS: The average age was 48 years. A mean number of nodes of 6.5/groin was found. In zone II, which is our zone of interest a mean of 3.1 nodes were counted with a mean size of 7.8 mm. In three patients no nodes were found in zone II. In five patients nodes were seen in zone II but were not sufficient in size or number to be considered a lymph node unit. On average the lymph node unit in zone II was found to be 48.3 mm from the pubic tubercle when projected on a line from the pubic tubercle to the anterior superior iliac spine, 16.0 mm caudal to this line, and 20.4 mm above the groin crease. On average the lymph node unit was a mean of 41.7 mm lateral to the SCIV-SIEV confluence. CONCLUSION: This study provides increased understanding of the lymphatic anatomy in zone II of the groin flap and suggests a refined technique for designing the VGLNF. As with any flap there is a degree of individual patient variability. However, having information on the most common anatomy and flap design is of great value.

The 5th world symposium for lymphedema surgery-Recent updates in lymphedema surgery and setting up of a global knowledge exchange platform.

The successful completion of the 5th World Symposium for Lymphedema Surgery (WSLS) marks another milestone in the development and advancement of the management of lymphedema. We present our experience in organizing such a scientific lymphedema conference as well as a summary of seven variable live surgeries used for treating lymphedema. An update of current knowledge and determination of future direction in the treatment of lymphedema was made possible via WSLS 2016. J. Surg. Oncol. 2017;115:6-12. © 2016 Wiley Periodicals, Inc.

The surgical anatomy of the vascularized lateral thoracic artery lymph node flap-A cadaver study.

BACKGROUND: One promising surgical treatment of lymphedema is the VLNT. Lymph nodes can be harvested from different locations; inguinal, axillary, and supraclavicular ones are used most often. The aim of our study was to assess the surgical anatomy of the lateral thoracic artery lymph node flap. MATERIALS AND METHODS: In total, 16 lymph node flaps from nine cadavers were dissected. Flap markings were made between the anterior and posterior axillary line in dimensions of 10 × 5 cm. Axillary lymph nodes were analyzed using high-resolution ultrasound and morphologically via dissection. The cutaneous vascular territory of the lateral thoracic artery was highlighted via dye injections, the pedicle recorded by length, and diameter and its location in a specific coordinate system. RESULTS: On average, 3.10 ± 1.6 lymph nodes were counted per flap via ultrasound. Macroscopic inspection showed on average 13.40 ± 3.13. Their mean dimensions were 3.76 ± 1.19 mm in width and 7.12 ± 0.98 mm in length by ultrasonography, and 3.83 ± 2.14 mm and 6.30 ± 4.43 mm via dissection. The external diameter of the lateral thoracic artery averaged 2.2 ± 0.40 mm with a mean pedicle length of 3.6 ± 0.82 cm. 87.5% of the specimens had a skin paddle. CONCLUSIONS: The lateral thoracic artery-based lymph node flap proved to be a suitable alternative to other VLNT donor sites.

Comparison of long-term clinical outcomes among different vascularized lymph node transfers: 6-year experience of a single center's approach to the treatment of lymphedema.

BACKGROUND: This study evaluated the long-term clinical outcomes among different vascularized lymph node transfers (VLNT) used at our institution. METHODS: Between July 2010 and July 2016, all patients with International Society of Lymphology (ISL) stages II-III who underwent VLNT were evaluated. Demographic and clinical data (limb circumference, infectious episodes, lymphoscintigraphic studies) were recorded pre-operatively. Clinical outcomes, complications, and additional excisional procedures were analyzed post-operatively. At least 2-year follow-up was required for inclusion. RESULTS: Overall, 83 patients (Stage II:47, Stage III:36) met the inclusion criterion. Mean follow-up was 32.8 months (range, 24-49). Lymph node flaps used were groin (n = 13), supraclavicular (n = 25), gastroepiploic (n = 42), ileocecal (n = 2), and appendicular (n = 1). Total mean circumference reduction rate was 29.1% (Stage II) and 17.9% (Stage III) (P < 0.05). A paired t-test showed that VLNT significantly decreased the number of infections (P < 0.05). Three patients reported no improvement of the symptoms. Major complications included one flap loss and one donor site hematoma. After the period of follow-up, 18 patients (21.7%) underwent additional excisional procedures. CONCLUSION: VLNT is a promising technique used for the treatment of lymphedema and appears to be more effective in moderate stages (Stage II). Patients with advanced stage lymphedema (Stage III) may benefit from additional excisional procedures.

Platysma-sparing vascularized submental lymph node flap transfer for extremity lymphedema.

BACKGROUND AND OBJECTIVES: Due to its consistent vascular and lymphatic anatomy, the vascularized submental lymph node flap is a reliable option for lymphedema treatment. Despite these advantages, flap harvest requires resection of platysma, which may cause a marginal mandibular nerve pseudo-paralysis. The aim of this study was to investigate the donor site morbidity of an innovative platysma-sparing vascularized submental lymph node flap transfer for treating extremity lymphedema. METHODS: Ten patients undergoing platysma sparing submental lymph-node flap harvest were prospectively enrolled in the study and compared with a control group of 10 patients who underwent standard submental lymph-node flap harvest. Photogrammetry analysis was used to assess donor site morbidity with regards to marginal mandibular nerve pseudo-paralysis. RESULTS: All flaps survived. No necrosis of the skin paddle was observed in both groups. There were no marginal mandibular nerve palsies in both group. There were no cases of marginal mandibular nerve pseudo-paralysis in the platysma sparing group. CONCLUSIONS: The platysma sparing submental flap, while offering comparable functional improvement for extremity lymphedema, has the advantages of maximizing nerve and muscular preservation, significantly reducing donor site morbidity. J. Surg. Oncol. 2017;115:48-53. © 2017 Wiley Periodicals, Inc.

A head-to-head comparison among donor site morbidity after vascularized lymph node transfer: Pearls and pitfalls of a 6-year single center experience.

Between 2010 and 2016, 110 patients with extremity lymphedema underwent vascularized lymph node (VLN) transfer: groin (G-VLN = 20), supraclavicular (SC-VLN = 54), and right gastroepiploic (RGE-VLN = 36) open and laparoscopic approach. Herein, we discuss the pearls and pitfalls for VLN harvest and compare donor site morbidity and complications. Lymphatic leakage: G-VLN (n = 1) and SC-VLN (n = 1) and one hematoma: SC-VLN were found. Laparoscopic harvest of the RGE-VLN reduces donor site morbidity. However, surgeons experience is imperative to minimize donor site morbidity and complications. J. Surg. Oncol. 2017;115:37-42. © 2016 Wiley Periodicals, Inc.

Surgical anatomy of the vascularized submental lymph node flap: Anatomic study of correlation of submental artery perforators and quantity of submental lymph node.

BACKGROUND: Harvesting the submental flap for vascularized lymph node transfer (VLNT) presents a challenging procedure because of, the topographic variation of the submental artery (SA) and the marginal mandible nerve (MMN) and the limited pedicle length for a free tissue transfer. The aim of this study was to evaluate surgical anatomical landmarks and variations of the submental lymph node flap (SLNF). METHODS AND MATERIALS: The authors examined the characteristics and landmarks of 18 SLNF in nine fresh cadavers. The diameter, length, and caliber of the SA and its relation to bony anatomic landmarks were measured. In addition, the number of lymph nodes (LNN) was evaluated through dissection and ultrasound. RESULTS: Within the designated SLNF (10 × 5 cm2 ), the number of LNN was on average 3 ± 0.6, with an average size of 4.5 ± 1.8 mm × 2.9 ± 1.2 mm. Projection of the LNN on the mandible, measured from the gnathion (GT, median-sagittal-plane) toward the gonion (GN, mandibular angle), was at 63.4 ± 5.8 mm (e.g., 65%) of the mandible for the first lymph node (LN), and for the following LNN was at 50.4 ± 7.7 mm (e.g., 52%), 44.0 ± 8.6 mm (e.g., 45%), and 40.50 ± 2.1 mm (e.g., 42%). The MMN consistently crossed the mandible body and the facial artery (FA) from dorso-caudal to ventro-cranial at 72 ± 5.2 mm, e.g., 75% of the mandible's length. Here, the nerve always lay superficial to the FA and was on average 0.96 ± 0.14 mm in diameter. Submental artery was located on average at 64 mm (e.g., 66%) of the mandible, with an average diameter of 1.34 ± 0.2 mm. CONCLUSION: The submental lymph node flap has a constant vascular supply by the submental artery. Lymph node count is on average three. Lymph nodes are close to the submental artery and its perforators. Marginal mandibular nerve lies superficial to the facial artery and crosses the artery at 75% of the mandible body length (gnathion to gonion = 100%). J. Surg. Oncol. 2017;115:54-59. © 2016 Wiley Periodicals, Inc.

Delayed grafting for banked skin graft in lymph node flap transfer.

Over the last decade, lymph node flap (LNF) transfer has turned out to be an effective method in the management of lymphoedema of extremities. Most of the time, the pockets created for LNF cannot be closed primarily and need to be resurfaced with split thickness skin grafts. Partial graft loss was frequently noted in these cases. The need to prevent graft loss on these iatrogenic wounds made us explore the possibility of attempting delayed skin grafting. We have herein reported our experience with delayed grafting with autologous banked split skin grafts in cases of LNF transfer for lymphoedema of the extremities. Ten patients with International Society of Lymphology stage II-III lymphoedema of upper or lower extremity were included in this study over an 8-month period. All patients were thoroughly evaluated and subjected to lymph node flap transfer. The split skin graft was harvested and banked at the donor site, avoiding immediate resurfacing over the flap. The same was carried out in an aseptic manner as a bedside procedure after confirming flap viability and allowing flap swelling to subside. Patients were followed up to evaluate long-term outcomes. Flap survival was 100%. Successful delayed skin grafting was done between the 4th and 6th post-operative day as a bedside procedure under local anaesthesia. The split thickness skin grafts (STSG) takes more than 97%. One patient needed additional medications during the bedside procedure. All patients had minimal post-operative pain and skin graft requirement. The patients were also reported to be satisfied with the final aesthetic results. There were no complications related to either the skin grafts or donor sites during the entire period of follow-up. Delayed split skin grafting is a reliable method of resurfacing lymph node flaps and has been shown to reduce the possibility of flap complications as well as the operative time and costs.

Septum-based cervical lymph-node free flap in rat: a new model.

BACKGROUND: A limited number of lymph node flap models are available in rats, and none of them include a skin paddle. The aim of this study was to describe a new cervical lymph node-adipo-cutaneous flap model in the rat for future experimental studies. MATERIAL AND METHODS: Fifteen Wistar rats were used. In four, neck anatomy was investigated with special focus on cervical lymph nodes. In eleven rats, a lymph node flap with a skin paddle of 1.5 × 0.5 cm centered along the surface projection of the innominate septum was harvested and transferred to the inguinal region. The rats were followed-up for 7 d. At 30-d postoperatively, the lymphatic flow restoration with the recipient limb lymphatics was assessed with methylene blue, and histology was performed on excised flaps. RESULTS: According to the anatomic findings, the flap was based on an innominate septum which was a well-defined adipofascial structure containing glandular vessels to the surrounding tissues and located between submandibular-sublingual glandular complex and parotid gland. Flap's microvascular and lymph node anatomy (two to three lymph nodes) was constant. Donor-site morbidity was minimal, and all flaps survived. At 30-d postoperatively, the restoration of the lymphatic flow with the recipient limb lymphatics was observed, and histology revealed viable lymph nodes. CONCLUSIONS: The constant anatomy, the possibility to include a skin paddle and the minimal donor-site morbidity, make this flap a safe, reliable, and versatile lymph node flap supermicrosurgical model for autologous transplant in the rat for future experimental studies.

Technical details for inset of flaps in transfer of double-level gastroepiploic lymph node flaps for lower extremity lymphedema.

BACKGROUND: In this study, the method that can be followed to ensure rapid and uncomplicated recovery of lymph node flap (LNF) applied in the medial of the ankle for lymphedema treatment was investigated. METHODS: Thirty-seven patients with class II of lower limb lymphedema underwent transfer of gastroepiploic LNF to the medial ankle and popliteal fossa areas. At the popliteal fossa region, the wound could always be closed primarily by the advancement of neighboring skin. The wound closure could be classified into three types at the medial ankle area (A) The partially exposed LNF was covered with a split-thickness skin graft (STSG) (n = 9). (B) A larger local flap was elevated, and the donor site of the local flap was covered with STSG (n = 18). (C) The skin flap's donor site was treated with pre-tie sutures (n = 10). RESULTS: In the popliteal region, there was no complication of wound healing. In the ankle region, the wound was coated by a thin layer of hematoma over the exposed LNF in 5 patients of group A. It healed secondarily except for one patient who needed a secondary skin graft. The healing was perfect in group B. In group C the healing was good, but there was a hypertrophic scar in 7 patients and required steroid injection later. CONCLUSION: To avoid complications of the gastroepiploic LNF at the medial ankle, it should be entirely covered by an anteriorly-based local flap, and the donor site defect of the local flap can be treated with either pre-tie sutures or a skin graft.

Vascularized lymph node flaps can survive on venous blood without an arterial inflow: an experimental model describing the dynamics of venous flow using indocyanine green angiography (With video).

Background: Several surgeons have described studies of free-tissue transfers using veins instead of arteries. These innovative microsurgical techniques can offer several advantages, such as an easier dissection during flap harvesting, and represent an alternative during an accidental surgical mistake or development of new surgical procedures. The purpose of this study was to describe and explore different constructs of vascularized lymph node transfer (VLNT) only based on venous blood flow in a mouse model, evaluate their blood flow microcirculation through indocyanine green (ICG) angiography and investigate the lymphatic drainage function and the lymph nodes' structures. Methods: Five types of venous lymph node flaps (LNF) were created and investigated: Types IA, IB, IC, IIA and IIB were developed by ICG intraoperatively (with videos in the article). Seven weeks later, by applying methylene blue, the recanalization of the lymphatic vessels between the LNF and the recipient site was detected. Lymph nodes were collected at the same time and their structures were analyzed by hematoxylin and eosin staining analysis. Results: All of the venous LNFs developed except Type IC. Seven weeks later, methylene blue flowed into Types IA, IB, IIA and IIB from recipient sites. When comparing with arteriovenous lymph node, the medullary sinus was diffusely distributed in venous lymph nodes. The proportion of cells was significantly reduced (p < 0.05). The artery diameters were significantly smaller (p < 0.05). The veins diameters and lymphatic vessels output in Types IA, IB, IIA and IIB were more dilated (p < 0.05). Conclusions: This research demonstrated that Type IA, IB, IIA and IIB venous LNFs can retrogradely receive venous blood supply; they can survive, produce a lymphatic recanalization and integrate with the surrounding tissue, despite lymph node structural changes. Our results will improve the understanding of the survival mechanism of venous LNFs and will help researchers to design new studies or lymphatic models and eventually find an alternative procedure for the surgical treatment of lymphedema.

Clinical application of magnetic resonance lymphangiography in the vascularized omental lymph nodes transfer with or without lymphaticovenous anastomosis for cancer-related lower extremity lymphedema.

Background: The recent increase in the number of patients with lower extremities lymphedema and the development of microsurgery techniques have led to a rise in lymphedema treatment. Vascularized omental lymph node transfer (VOLT), an emerging treatment modality for extremity lymphedema, has shown its unique advantages in reconstructing lymphatic circulation and absorbing exudated lymphatic fluid. Patients who underwent radical tumor resection with/without radiation therapy treatment often present with impairment or degeneration of the inguinal lymph nodes. For such cases, VOLT could provide adequate lymph nodes and tissue to absorb edema fluid in these areas. Therefore, we analyzed the operative outcomes of VOLT under the guidance of magnetic resonance lymphangiography (MRL) in this study, as this individualized and precise surgical procedure could benefit patients and improve their quality of life. Methods: From November 2021 to September 2022, a total of 14 patients' 19 legs with extremity lymphedema underwent a VOLT with or without lymphaticovenous anastomosis (LVA). Outcomes, including circumference reduction rates, preoperative and postoperative MRL results, and other complications, were analyzed. Results: The mean follow-up period was 8.86±1.41 months (range, 7-11 months). The mean circumference reduction rates {circumference reduction rate (%) = [1 - (postoperative affected limb - healthy limb)/(preoperative affected limb - healthy limb)] × 100%} of different planes (i.e., ankle, 10 cm above the knee, 10 cm below the knee, 10 cm above the ankle, and 20 cm above the knee) were 15.64%±40.08%, 11.79%±30.69%, 20.25%±24.94%, 7.73%±30.05%, -1.517%±16.75%. Notably, one patient had multi-drug-resistant gram-negative infections, which resulted in the loss of three flaps. The postoperative MRL showed improved lymphatic drainage and lower extremity volume in the remaining 13 cases. Conclusions: The precision evaluation of inguinal lymph nodes and lower extremities lymphatic system through MRL using VOLT can provide surgeons with a comprehensive understanding and reliable evidence for the treatment of cancer-related lower extremity lymphedema.

Evaluation of the External Jugular Vein Overlying the Sternocleidomastoid Muscle as Venous Lymph-Node Flap.

BACKGROUND: Until recently, vascularized lymph-node flaps were based on arterial and venous donor vessels. Now, venous lymph-node flaps form a novel promising concept in the treatment of advanced-stage lymphedema. In preliminary studies, the external jugular vein has shown promising results as a venous lymph-node flap. However, nothing is known about the number of lymph nodes adjacent to the external jugular vein. METHODS: Standardized specimens of the external jugular vein and surrounding fatty tissue directly overlying the sternocleidomastoid muscle were obtained during routine neck dissection. Histologic evaluation was performed in order to evaluate for the presence of lymph nodes within the tissue. RESULTS: A total of 20 specimens were evaluated. There was no vein in 4 of the samples. We found lymph nodes in 9 of the remaining 16 samples. In 7 samples, lymph nodes were absent. CONCLUSION: Our results suggest that the vein directly overlying the sternocleidomastoid muscle may not be the ideal candidate for a venous lymph-node flap.

Gastroepiploic vascularized lymph node transfer for extremities' lymphedema: Is two better than one? A retrospective case-control study.

Single (SG-VLN) and double gastroepiploic vascularized lymph node transfer (DG-VLN) have shown promising results for the treatment of extremities' lymphedema. The literature search yields only few other cases describing outcomes following double VLN transfers, but no comparative studies have been produced so far. The aim of this study was to retrospectively examine and compare the effects of SG-VLN versus DG-VLN transfer. All patients diagnosed with extremities' stage II and III lymphedema who had undergone SG-VLN or DG-VLN between January 2012 and December 2018 were identified from two institutions' databases. Demographic and surgical data were collected. The primary endpoint was the comparison of the reduction in limb circumference (CRR) within 12 months post-surgery. Secondary endpoints included the reduction of cellulitis episodes and patients' quality of life improvement. Eighty-nine patients met the inclusion criteria. At 12 months of follow-up, higher CRR values were observed in the double inset group (p<0.05*) both at above elbow/above knee (AE/AK) level (SG-VLN: 70.6% ± 0.6%; DG-VLN: 72.2% ± 0.7%) and at below elbow/below knee level (SG-VLN: 59.1% ± 1.3%; DG-VLN: 61.6% ± 3.7%). Subgroup analyses of the involved limb (upper vs lower) were consistent with the primary treatment effects. The reduction of cellulitis episodes did not differ between the two groups, while the DG-VLN group showed better results in the overall satisfaction function, symptoms, and mood domains of the LYMQoL questionnaire (p=0.04). The study suggests that either single or double transfer can produce excellent results, but double inset of the gastroepiploic VLNT flap may produce greater volume reductions both at 12 and 24 months. Further studies with a larger sample size are warranted to corroborate our results.

Anatomy and relationships of forelimb lymph nodes in Sprague-Dawley rats: A detailed dissecting approach.

Background: Constructing a reliable animal model for preclinical treatment of secondary lymphedema is challenging because the anatomical characteristics near the lymph nodes are understudied. Therefore, this study examined the detailed anatomical relationship between the axillary lymph node flaps (ALNFs) and brachial lymph node flaps (BLNFs) in the forelimb of Sprague-Dawley (SD) rats. Materials and methods: Ten male rats, weighing 250-300 g, were used. The ALNFs and BLNFs on either side of the rat forelimbs were dissected. The two lymph node flaps (LNFs) were immediately harvested to analyze their physical characteristics (via imaging process software) and microscopic structure (via histology examinations). Results: A total of 20 ALNFs and BLNFs from 10 rats were harvested and analyzed. ALNF dissection was simpler and lasted a shorter time than BLNF dissection (p < 0.0001). The left LNFs were more difficult to dissect than the right LNFs (p < 0.0001). In physical characteristics of LNFs, the area (p < 0.001) of LNFs and the number of lymph nodes (p < 0.0001) associated with ALNFs were greater than those associated with BLNFs, but the pedicle lengths of ALNFs were shorter than that of BLNFs (p < 0.0001). No significant difference in the diameter of the venous and arterial pedicles was noted between the two LNFs (p > 0.05). Conclusion: This study reported detailed physical characteristics of ALNFs and BLNFs in SD rat forelimbs, assessing the respective area of LNFs, number of lymph nodes, and lengths and diameters of vascular pedicles. Moreover, this study suggested an efficient method to perform a study of LNFs by describing the operation process and repeatedly measuring the operation time.