The normal anatomy of the lymphatic system in the human leg

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.

Coformulation with Tattoo Ink for Immunological Assessment of Vaccine Immunogenicity in the Draining Lymph Node

Characterization of germinal center B and T cell responses yields critical insights into vaccine immunogenicity. Nonhuman primates are a key preclinical animal model for human vaccine development, allowing both lymph node (LN) and circulating immune responses to be longitudinally sampled for correlates of vaccine efficacy. However, patterns of vaccine Ag drainage via the lymphatics after i.m. immunization can be stochastic, driving uneven deposition between lymphoid sites and between individual LN within larger clusters. To improve the accurate isolation of Ag-exposed LN during biopsies and necropsies, we developed and validated a method for coformulating candidate vaccines with tattoo ink in both mice and pigtail macaques. This method allowed for direct visual identification of vaccine-draining LN and evaluation of relevant Ag-specific B and T cell responses by flow cytometry. This approach is a significant advancement in improving the assessment of vaccine-induced immunity in highly relevant nonhuman primate models.

Fetal anatomy of peripheral lymphatic vessels: a D2-40 immunohistochemical study using an 18-week human fetus (CRL 155 mm)

We demonstrated fetal peripheral lymphatic vessels (LVs) using D2-40 immunohistochemistry in a whole female fetus (18 weeks of gestation, CRL 155 mm) except for the head. There were abundant LVs in the thyroid gland, lung, stomach, small intestine, rectum and pancreas, whereas no LVs were seen in the parathyroid gland, spleen and adrenal cortex. In the liver, except for the gallbladder bed, LVs were still restricted to around hilar thick portal veins and around the hepatic vein terminals. Subcutaneous LVs were well developed throughout the body even in areas where no or few perforating LVs connected with the deep LVs. The diaphragm contained abundant, dilated LVs in the pleural half of its thickness. LVs were also seen not only along supplying arteries of muscles and cartilage but also along the epimysium and perichondrium. LVs ran in a space between the obliquus internus and transversus abdominis but not between the obliquus internus and obliquus externus. Some tight connective tissues such as the sacrotuberous ligament contained abundant LVs. The intervertebral foramen contained a lymphatic plexus. The present observations provide a better understanding of peripheral lymphatic development. The fetal lymphatic morphology seems not to represent a mini-version of the adult morphology.

A newly designed SIPC device for management of lymphoedema

PURPOSE

Using (Sequential) intermittent pneumatic compression (SIPC) is one of the most appropriate nonsurgical treatments for lymphoedema. In this study, we introduce a new mode for SIPC and evaluate its clinical results with higher pressures.

METHODS

Participants included 43 lower limb lymphoedema patients who underwent high pressure SIPC. Limb circumference pre- and post-SIPC were evaluated.

RESULTS

The mean reduction of the affected limb oedema was approximately 75%, which is regarded as a good response to the short-term treatment. Patients with disease duration more than 20 years didn't show a good or excellent response. Also the foot area had the least degree of reduction of oedema.

CONCLUSION

We concluded that, the suggested mode may provide more acceptable results compared with the other This mode allows unidirectional forward lymph flow and associated high pressure usage well tolerated in chronic cases of the disease.

Femoral incision morbidity following endovascular aortic aneurysm repair

Currently available aortic stent-grafts require bilateral femoral incisions for device deployment. The incidence of morbidity (infection, lymphatic complications, breakdown) of vertical, infrainguinal incisions used in endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAAs) was assessed, and the natural history of asymptomatic groin fluid collections following such procedures was determined. Between June 1999 and February 2001, 77 consecutive patients underwent EVAR for AAAs utilizing bilateral vertical femoral incisions. Fifty-nine (77%) bifurcated stent-grafts (BSGs), and 18 (23%) aortouniiliac (AUI) devices, with femorofemoral bypass were performed. Patients returned at 2 weeks, 1 month, and 6 months for physical examination, and 1 month and 6 months for abdominal and pelvic computed tomography (CT) scans. The presence of fluid collections was determined from the dictation report of the attending radiologist. Data are reported as (n) mean +/-SE. Patient characteristics were compared using Fisher's exact test; p<0.05 considered significant. There were 72 males and 5 females, age 75 +/-6.4 years and aneurysm size (77) 5.6 +/-0.8 cm. There were no cases of wound breakdown or lymph fistula. Wound infections occurred in 3/150 incisions (2%), 2/34 AUI incisions (6%), and 1/116 BSG incisions (0.86%). There was no statistical difference (p=0.13) between graft types (BSG vs AUI). All infections were diagnosed clinically before the 1-month CT scan, treated without operative intervention or hospitalization, and resolved. There was a significant decrease in the BSG group and overall in asymptomatic wound fluid collections from 1 to 6 months postoperatively. At 1 and 6 months, respectively, the BSG group had 17 (14.6%) and 3 (2.6%) fluid collections out of 116 incisions (p=0.003); the AUI group had 6 (17.6%) and 1 (2.9%) fluid collection(s) out of 34 incisions (p=0.13); and overall 23 (15.3%) and 4 (2.6%) out of 150 incisions (p=0.004). The present study demonstrates that bilateral vertical femoral incisions used in EVAR have a wound infection rate of 2.0%. Infections are usually detected and treated clinically and empirically without the need for hospitalization or surgery. Asymptomatic groin wound fluid collections resolve significantly within 6 months without intervention. Therefore, surgical femoral artery exposure adds little morbidity to the endovascular repair of abdominal aortic aneurysms.

The value of the oblique groin incision for femoral artery access during endovascular procedures

Groin incisions for access to femoral vessels are typically made in a vertical fashion extending across the groin crease. Significant morbidity can be associated with these incisions, including lymphoceles, lymph fistulae and infections, as documented in the infrainguinal revascularization literature. We have adopted an oblique groin incision for femoral artery access during endovascular graft reconstruction of the aorta because of the potential for reduced wound morbidity. In this study we report our experience with this technique and compare it with the existing literature to determine its usefulness. From June 1998 to May 1999, 98 consecutive patients received endovascular exclusion of aortic aneurysms at The Mount Sinai Medical Center, New York. Patients were treated with aortoaortic (24), aortouniiliac with femorofemoral crossover bypass (41), or bifurcated endografts (33) and were prospectively studied for wound complications. Aortoaortic procedures required one inguinal incision whereas aortouniiliac with femorofemoral crossover bypass and bifurcated procedures employed bilateral inguinal wounds. Wound complications were defined as cellulitis, subcutaneous purulence, femorofemoral graft infection, lymphocele, or lymphocutaneous fistulae. The oblique groin incision allows adequate exposure to the femoral arteries and is associated with low wound morbidity. We suggest that this approach may be the preferred technique for access to femoral arteries during endovascular procedures, and should be considered for infrainguinal arterial reconstructions.

Lower limb oedema following distal arterial bypass grafting

Lower-limb oedema following arterial bypass surgery for ischemia is a common sequela which can complicate wound healing or delay resumption of mobility. Its exact pathogenesis remains uncertain but many theories have been proposed. Lymphatic disruption during arterial exposure, and endothelial damage from atrophy of the media and oxygen-derived free radical release are currently favoured hypotheses. Infrequently, deep vein thrombosis follows surgery and may exacerbate the condition. Efforts aimed at reducing the oedema, such as the use of lymphatic preserving incisional approaches or the use of antioxidants, have given conflicting results. The use of compression hosiery and leg elevation appear to be the most effective measures in reducing postoperative lower limb oedema.

Groin lymphorrhea complicating revascularization involving the femoral vessels

Seven (4%) of 193 patients developed lymphoceles in 8 (2%) of 316 groin wounds after 211 arterial reconstructive procedures. Included were 91 aortic, 15 extra-anatomic, and 105 infrainguinal revascularizations. Lymphoceles developed in otherwise uncomplicated wounds in 6 (8%) of 73 patients with oblique incisions and bilaterally in 1 (1%) of 120 patients with vertical incisions (p = 0.01). This difference may be related to the surgical technique, with increased lymphatic damage and inadequate wound closure in the oblique approach. No increased incidence of lymphorrhea was noted in those patients undergoing aortic reconstruction regardless of the type of incision used (p = 0.15), or when compared with patients who had undergone extra-anatomic or infrainguinal bypass (p = 0.14). Each lymphocele was persistent, and external fistulas spontaneously occurred in three. Diagnosis was based upon clinical awareness and the appearance of the groin mass. Conservative management was uniformly unsuccessful, and operative ablation of the lymph fistula and lymphocele proved to be definitive therapy.

Vacuum drainage of groin wounds after vascular surgery: a controlled trial

A pilot study of 100 consecutive groin wounds after vascular surgery demonstrated lymph leaks in 12 per cent. Lymph leak was significantly associated with wound infection and with prolongation of in-patient stay. A controlled trial was therefore instituted to assess the influence of vacuum drainage in groin wound healing. One hundred and twenty-seven wounds were randomized to drainage (n = 65) or no drainage (n = 62) and the wounds were examined 'blind' by independent observers. No difference in the incidence of lymph leakage or wound infection was noted between the two groups. The routine use of suction drainage for groin wounds in vascular surgery is unnecessary.

The effect of the canine popliteal node on the composition of lymph

The composition of afferent lymph draining into the canine popliteal lymph node was compared with that of the efferent lymph leaving the node. Both the protein and cellular composition were studied. In twenty-five greyhounds the protein concentration of efferent lymph was greater than that of afferent lymph collected from the same limb. Although the absolute level of protein varied greatly between dogs, in a particular animal there was a constant ratio between the protein content of afferent and efferent lymph. The concentration of protein in efferent lymph was approximately double that of afferent lymph. Chromatographic analysis of lymph and the use of radio-iodinated canine albumin indicated that the reason for the increased level of protein in the efferent lymph is that the popliteal node concentrates the protein in afferent lymph. Afferent lymph contained less than 3 X 10(3) cells/ml; efferent lymph contained between 0.5 X 10(6) and 4.3 X 10(6) cells/ml, 98% of which were lymphocytes. In different dogs there was no correlation between efferent lymphocyte density and afferent or efferent protein concentration; however, when an afferent lymphatic was perfused with solutions of different protein concentration, the lymphocyte number in the efferent fluid became greater as protein concentration in the afferent perfusate was increased. The concentrating effect of the node is discussed in terms of its significance to both fluid balance and immunological surveillance.

The effect of human peripheral lymph on cell growth in vitro

Peripheral lymph is similar in composition to the interstitial fluid that surrounds most cells in vivo. Gel filtration is used to show that the protein composition of such lymph is considerably different from that of plasma. Primary cell cultures fail to survive in adult human plasma or serum but grow well in adult peripheral lymph collected from the dorsum of the foot. The different effects on cell cultures may be because toxic components such as low-density lipoproteins are partially filtered out by the capillary endothelium.

Comparison of lymphedema following incontinuity and discontinuity groin dissection

Wide excision of primary malignant melanoma en bloc with regional lymphadenectomy decreases the incidence of regional recurrence as compared with a discontinuous dissection. The more extensive soft tissue defect of the incontinuity procedure is of concern since major lymphatics are often ablated from the ankle region up to the aortic bifurcation. This problem was studied in 81 currently living patients, all of whom had been operated upon for primary melanoma located below the distal thigh. Measurable lymphedema was found in 64% who had had the incontinuity procedure and 69% in the discontinuity group. The incidence of advanced lymphedema (greater than two inches) was 23% and 36%, respectively. All patients with advanced edema had been operated upon more than 3 years ago. Eighty per cent of patients operated upon more than 5 years ago had lymphedema. Wound complications had occurred in 41% of the patients in the incontinuity group and 42% in the discontinuity group, but this did not affect the incidence of edema. The clinical findings are readily explainable on the basis of lymphangiographic data.

The influence of the lymph node on the protein concentration of efferent lymph leaving the node

1. Experiments have been performed in sheep to determine the contribution of lymph formed within a lymph node to the total protein output in lymph leaving the node. 2. The lymphatic duct leaving the popliteal lymph node was cannulated and the protein and lymphocyte output in efferent lymph determined. The afferent lymph flow to the popliteal node was then diverted and lymph formed only within the lymph node collected from the efferent cannula. It appeared from the results that the popliteal lymph node forms lymph at the rate of approximately 1 ml. per hour and may contribute 30-50% of the protein output observed in efferent lymph. 3. The importance of lymph formation within the lymph node varied between nodes found in different regions of the body. This was due in part to the different protein concentrations in the afferent lymph to the different nodes. 4. A positive correlation was found between the protein and lymphocyte concentrations in efferent lymph from the popliteal lymph node in seven out of eleven sheep and in lymph formed within the popliteal lymph node in two out of three sheep. It is suggested that this relationship may be due to an increased transfer of plasma proteins through the post-capillary venules in the lymph node accompanying the continual traffic of lymphocytes across the wall of these vessels. The results indicated that the protein transfer across the post-capillary venules was not an indiscriminate transfer of plasma per se but a selective transport from the blood plasma compartment based on molecular size.

Septic arthritis in association with primary lymphoedema

The association between b-haemolytic streptococcal arthritis of the knee and primary lymphoedema is reported. This condition appears to resolve slowly using conventional methods of treatment, in the form of immobilisation and antibiotic therapy. However, the penetration of penicillin into the joint in these two patients was adequate, suggesting that there is no place for the intra-articular injection of antibiotic in the treatment of this condition.

Lymph flow and lymph protein concentration in the skin and muscle of the rabbit hind limb

1. Three lymphatic beds have been found in the rabbit hind limb:(i) the lymph from the foot and ankle drains into lymphatics which run with the deep veins to the popliteal node;(ii) the superficial lymphatics of the medial skin from mid-calf to the groin enter the inguinal node while those of the lateral skin drain into the popliteal node;(iii) the lymph draining the muscles collects in vessels which do not enter the popliteal node but join the femoral lymphatic post-nodally.2. The lymphatic system of the hind limb is regionalized so that lymph from a specific area enters the popliteal node in one specific lobe and no other.3. By cannulating the femoral lymphatic and ligating the post-nodal lymph vessel close to the point at which it leaves the node it was possible to collect pure muscle lymph.4. The mean muscle lymph flow was 21 mul./100 g.min whilst the skin lymph flow was 240 mul./100 g.min. The mean protein concentration of muscle lymph was usually somewhat higher than that of skin lymph.5. After nerve stimulation there was an increase in muscle lymph flow but no increase in protein concentration.6. After a mild thermal injury there was no change in muscle lymph flow or its protein concentration, but there was an enormous increase in the leakage of lactic dehydrogenase indicating considerable cellular injury. On the other hand a significant increase in both protein concentration and flow of skin lymph occurred after thermal injury.