A number of different donor sites exist for vascularized lymph node transfer that have near-equivalent success rates in improving the condition of patients suffering from lymphedema.
Donor site selection should be based on surgeon comfort and experience, taking into account patient expectations and availability of donor sites, and with a thorough understanding and ability to manage complications.
Recipient site selection can be placed proximally, distally, or in both locations at the discretion of the lymphedema microsurgeon. Different philosophies exist regarding the precise mechanism of action, but successful outcomes have been documented with either location.
Lymphedema is a chronic debilitating condition that most frequently occurs after treatment for cancer in industrialized countries and has a significant detrimental impact on patients. Given that most malignancies mandate multimodality treatment, including surgical extirpation, chemotherapy, and radiation therapy, patients receiving this triad of treatment are placed at high risk of developing lymphedema especially when surgical resection also includes regional nodal dissection. While no cure currently exists for lymphedema, surgical strategies aimed to minimize the devastating sequelae of lymphedema can be categorized as ablative reductive procedures or physiologic procedures. Reductive procedures have generally been regarded as temporizing and aim solely to reduce the volume of the limb by removing the excess fluid and fat that have accumulated in response to the lymphedema. On the other hand, physiologic procedures are designed to address the underlying obstruction in the lymphatic system that has resulted secondary to surgery, trauma, infection, or occasionally an underlying hereditary condition.
One of the physiologic options that are gaining in popularity is vascularized lymph node transfer (VLNT), where functional lymph nodes are harvested from one location and transferred to the affected extremity in order to improve the drainage for the lymphedematous limb. A number of studies have demonstrated reproducible outcomes with high efficacy when the procedure is performed by well-trained, qualified microsurgeons. Despite the growing body of literature demonstrating successful improvements in patients’ symptoms and patient-reported outcomes, a number of questions remain unanswered, and the current chapter aims to address the selection of different donor sites and the rationale for placement and recipient sites in the affected limb. The donor sites will be reviewed in greater detail in their respective chapters, but the current chapter aims to provide an overview of donor site and recipient site characteristics to consider when performing VLNTs. Despite the myriad factors to consider, the optimal donor and recipient site remains an area of controversy among high-volume lymphedema surgeons.
Vascularized Lymph Node Donor Sites
With the increasing popularity of this approach, the number of available donor sites continues to grow. While the precise underlying mechanism of action is under considerable debate, two predominant theories exist as to how transferred lymph nodes improve the drainage from an affected extremity. One proposed mechanism is that the existing lymphatic architecture transferred with the lymph nodes will connect and inosculate with the existing lymphatic vessels in the limb, thereby restoring the drainage from the limb. Taken in combination with the hydrostatic pressure in the affected extremity, this favors fluid absorption into the transferred nodes, which is then returned into the systemic circulation through the venous anastomosis. An alternate hypothesis is the transferred lymph nodes stimulate neo-lymphangiogenesis, which then aids in the absorption of fluid and again improves the lymphedema and swelling in the extremity.
The critical components in the technique of lymph node transfer are based on the same premises similar to any other free flap routinely used for reconstruction following trauma, oncologic resection, or in hereditary defects. The selection of which donor site to use is largely dependent on surgeon preference and experience, including need for volume and pedicle size and length, as well as patient factors such as the availability of donor sites, concerns for the location of the scar, and the risks of iatrogenic donor site lymphedema following node harvest. However, with appropriate training and experience in supermicrosurgery, meticulous technique, proper preoperative planning and understanding of anatomy, and diligent postoperative monitoring, VLNT is reminiscent of other free tissue transfers. The operating surgeon needs to perform a careful dissection of the lymph nodes, making certain that the nodes are not devascularized during the harvest and the pedicle is sufficient for free tissue transfer. Preparation of the recipient site should have adequate recipient vessels, but the selection of recipient sites represents another area of considerable debate that will be discussed later in this chapter.
Donor Site Selection
As previously noted, a number of different donor sites for VLNT have been described, and the decision on which donor site to use is multifactorial. Clearly, in a patient with lower leg lymphedema, the use of the inguinal donor site is not an option and contraindicated. Similarly, for patients with upper extremity lymphedema following an axillary dissection, the ipsilateral lateral thoracic donor site has likely been removed with the formal axillary dissection, or at minimum, the pedicle is likely unreliable. Regardless of which donor site is selected, studies have demonstrated successful outcomes with all the described donor sites. Studies have also demonstrated equivalent outcomes in improving the quality of life in patients suffering from lymphedema, except for the lateral thoracic, which tended to have higher complication rates and lower success rates than other donor sites.
In the author’s opinion and experience, the different donor sites do have comparable outcomes and seem to be equally effective. The decision on which donor site to use depends predominantly on patient preferences, surgeon experience, and the risks and complication profile of each donor site. The patients should be educated on the location and visibility of the scar, the risk of damage and injury to adjacent structures, and the risk of donor site lymphedema. For the supraclavicular, lateral thoracic, and inguinal donor sites, preoperative lymphoscintigraphy should be performed to confirm the location of the sentinel nodes to minimize the risks of donor site lymphedema in harvesting the sentinel nodes draining the arm of the leg. At minimum, reverse lymphatic mapping should be performed again to minimize the risks of iatrogenic lymphedema when using these donor sites.
Submental Lymph Nodes
The submental nodes represent a reliable donor site for lymph node transfer popularized by Cheng, who has demonstrated remarkable outcomes in patients receiving a submental lymph node transfer both for upper and lower extremity lymphedema. The submental donor site reliably contains an average of five lymph nodes, and the anatomy is quite predicable. The flap is based on the submental artery, which can serve as the pedicle for the flap but is limited by size and length. If additional length and caliber are needed, the facial vessels can be dissected and used as the pedicle to the flap, which should be considered when deciding where to place the lymph nodes. For distal placement, a short pedicle can be sufficient, but if one opts to place the nodes into the axilla for example, a longer pedicle is useful and will facilitate the microsurgical anastomosis. There has not been any reported case of donor site lymphedema following harvest of the submental nodes, but patients should be cautioned regarding the location of the scar, which is quite visible, and the potential risk of injury to the marginal mandibular nerve. In taking the lymph nodes, skin can be included to add additional bulk if needed, but the nodes can be harvested without a skin paddle in order to limit the bulk if distal placement of the nodes is anticipated.
Supraclavicular Lymph Node Transfer
Another popular donor site for VLNT is the supraclavicular lymph nodes, which represent an average of eight nodes residing in a level 5 lymph node dissection. The flap is based off the transverse cervical vessels, which often provides an adequate caliber of vessels, but the length can often be quite limited, which can make proximal placement of lymph nodes, particularly in the axilla, very challenging ( Fig. 12.1 ). The variable vascular anatomy is discussed in a separate chapter but is a consideration when deciding on recipient vessels and recipient site. To compensate for the limited pedicle length, the dissection of recipient vessels should consider dissecting additional length to mobilize the recipient vessels into a more favorable position for the microvascular anastomosis. While a skin paddle can also be harvested with the lymph nodes, the perfusion of the skin paddle is less robust and reliable than the skin paddle of the other donor sites, but again can be beneficial to add additional bulk if needed. One of the earliest descriptions of the flap included a skin paddle, but over time, with increasing experience, Chang, who pioneered the use of the supraclavicular lymph node donor site, has largely abandoned the skin paddle. However, again, including a skin paddle will provide additional bulk with the lymph nodes and can also aid in postoperative monitoring of the flap but may be excessively bulky if the nodes are placed distally. The supraclavicular nodes can also be used to treat either upper or lower extremity lymphedema and can be taken without a skin paddle in order to limit the volume and bulk of the flap.
While there has only been one reported case of iatrogenic lymphedema following harvest of the supraclavicular nodes, the author recommends obtaining preoperative lymphoscintigraphy preoperatively to limit the risk of iatrogenic lymphedema. There is a percentage of the population who have the Mascagni-Sappey pathway whereby drainage of the arm proceeds through an alternate pathway from the axillary nodes. In those patients, disruption of the pathway by harvesting the supraclavicular nodes again can have catastrophic consequences in precipitating lymphedema or worsening a patient’s lymphedema. In general, the right side is preferable as well to avoid the risk of injuring the thoracic duct on the left side.
Lateral Thoracic Lymph Nodes
Historically, the lateral thoracic lymph node donor site has had the highest complication rates and lower efficacy than other donor sites ; however, with increasing knowledge, experience, and understanding, this is a donor site that can be used effectively for the treatment of both upper and lower extremity lymphedema. Preoperative lymphoscintigraphy should always be performed prior to harvest of the lateral thoracic nodes, along with reverse lymphatic mapping, in order to minimize the risks of donor site lymphedema. The pedicle to the lateral thoracic nodes is classically the lateral thoracic artery, which often provides more length than other lymph node donor sites. The lateral thoracic artery classically originates from the axillary artery but can also arise from the subscapular axis and the thoracodorsal vessels, or be absent altogether. In circumstances when the lateral thoracic pedicle is diminutive, the thoracodorsal vessels can also serve as a reliable pedicle. As with most lymph node transfers, the author favors including a skin paddle, but studies have demonstrated that in only 87.5% of the time is a perforator present that can supply the overlying skin.
While using the thoracodorsal vessels provides larger-caliber vessels and familiar anatomy for most plastic surgeons, this precludes the ability to perform a latissimus flap in the future. In a setting where the axillary dissection was limited to the anatomic boundaries of the axilla, the lateral thoracic nodes may have been preserved and can potentially be transferred both as a pedicle flap for proximal placement of the nodes into the axilla or as a free flap for VLNT. As with the other lymph node basins described, the use of a skin paddle is at the discretion of the lymphedema super microsurgeon but would be extremely bulky if the nodes are placed distally.
Inguinal Lymph Nodes
The inguinal lymph node donor site is a commonly used donor site due to familiarity with the anatomy and region of dissection. The superficial inguinal nodes are routinely harvested either as an independent lymph node transfer or coupled to a deep inferior epigastric perforator (DIEP) flap for breast reconstruction, where the nodes are transferred simultaneously with the flap to reconstruct the breast and address a patient’s lymphedema in one operation. In these circumstances, the nodes are placed proximally into the axilla.
The superficial inguinal nodes are typically based off the superficial circumflex iliac vessels but can also be based off the superficial inferior epigastric vessels as well. Extreme caution should be taken when harvesting the inguinal nodes, along with reverse mapping, to avoid injuring the lymphatic drainage of the leg or harvesting the sentinel nodes in the groin that can cause donor site lymphedema. The author recommends preoperative imaging with lymphoscintigraphy prior to harvesting the inguinal nodes, and anatomic landmarks should be observed. A skin paddle can be harvested reliably, which is essentially the harvest for a superficial circumflex iliac perforator flap if additional bulk is needed ( Fig. 12.2 ).