Inguinal Node Dissection

See Contemporary management of patients with penile cancer and lymph node metastasis (Nat Rev Urol 2007)

Indications

1. Clinically node-positive disease (palpable on physical exam)
2. Clinically node-negative disease (not palpable on physical exam) but increased risk for inguinal metastasis based on primary tumor characteristics (pT ≥2, presence of vascular or lymphatic invasion, or grade ≥3).
   • cN3 (fixed nodal mass) is managed initially with neoadjuvant chemotherapy followed by radical inguinal lymphadenectomy in responders

• May be curative when the disease is limited to the inguinal nodes.

Anatomic Considerations

• See Groin and Inguinal Anatomy Chapter Notes

Penile Lymphatics

• Superficial lymphatic system
  • Drains the prepuce and skin of the penile shaft
  • Empties into the right and left superficial inguinal nodes
• Deep lymphatic system
  • Drains the glans penis
  • Empties into the superficial inguinal nodes and the deep inguinal nodes
• Penetration of Buck’s fascia or the tunica albuginea by the primary penile tumor allows for dissemination of tumor cells into the lymphatic system
  • Primary site of metastatic spread of penile carcinoma occurs via the regional lymphatic system, first to the inguinal lymph node chain and then to the iliac and pelvic lymph nodes.
    • Presence and extent of regional LN metastases is the single most important prognostic factor in determining the long-term survival of patients with penile cancer
      • If cancer has spread to the pelvic nodes, long-term survival is < 10%
  • Inguinal metastatic spread can be unilateral or bilateral, and crossover drainage from the right to left groin or vice versa can also occur.
    • Metastatic spread from the inguinal lymph nodes to the contralateral pelvis or from the right to left pelvis has never been reported.
    • Skip lesions with direct lymphatic drainage from penile tumors to the pelvic lymph nodes has never been reported. .
    • Further spread from the true pelvis to the retroperitoneal lymph nodes is beyond the regional drainage system of the penis and represents systemic metastatic disease

Boundaries of Dissection§

• Superior: inguinal ligament
• Medial: anterolateral border of adductor longus muscle
• Lateral: sartorious muscle (saphenous vein and femoral vein in modified template)
• Inferior: apex of the femoral triangle/fossa ovalis (where the saphenous penetrates the fascia lata)
• Floor: pectineus muscle for deep dissection (fascia lata for superficial)
  • Note that adductor longus and sartorious are posterior to fascia lata and are therefore not the relevant medial and lateral boundaries for superficial dissection.

Open Inguinal Node Dissection

Videos

• Video 1
• Video 2

Equipment

• LigaSure™ Maryland jaw, 23cm length
• Sutures
  • 2-0 silk ties for lymphatics
  • 4-0 prolene on RB1 in case of vasculature injury
• Retractors
  • Rake retractor
  • Self-sustaining retractor
• Drains
  • Multiperforated closed-suction drains (10 or 15 French)

DVT Prophylaxis

• Compression boots only
  • Perioperative low-dose heparin may increase lymphatic leakage[1]

Position

• Thighs slightly abducted and externally rotated (frog-leg[2]) with cushioned support under the flexed knee.

Incision

• Oblique incision ≈2-3 cm below and parallel to the inguinal ligament (groin crease).

Standard radical inguinal lymphadenectomy

• In the standard radical inguinal lymphadenectomy, both the superficial and deep inguinal lymph nodes are removed
  • Superficial dissection removes nodes superficial to the fascia lata

Step by step

• See BJUI Surgical atlas. Surgical management of penile carcinoma: the inguinal nodes
• General anesthesia and insertion of lines. No need for naso/orograstric tube for gastric decompression during case.
• Patient positioning, antiseptic preparation, draping.
  • After induction of general anesthesia...
  • Trim hair overlying operative site, if needed
  • Insert 16-Fr Foley catheter
  • Externally rotate the hip and flex the knee
  • Use parking pen to denote landmarks and incision
    • Landmarks
      • Anterior superior iliac spine
      • Pubis
      • Inguinal ligament
  • Prepare area with chlorhexidine–alcohol scrub
    • Preoperative skin preparation with a chlorhexidine–alcohol scrub provided a significantly lower surgical site infection rate at 30 days when compared to a skin prep with a povidone–iodine solution
  • Drape with exposure of the umbilicus, pubic tubercle, anterior superior iliac spine, and anterior thigh
• Make skin incision[3]
  • Lateral end of incision is to a line drawn from the anterior superior iliac spine extending inferiorly and the medial end of the incision is to a line drawn from the pubic tubercle extending inferiorly
    • The inguinofemoral dissection is designed to cover an area outlined superiorly by a line drawn from the superior margin of the external ring to the anterior superior iliac spine, laterally by a line drawn from the anterior superior iliac spine extending 20 cm inferiorly, and medially by a line drawn from the pubic tubercle 15 cm down the medial thigh.[4]
    • If an area of the skin overlying the cancer-bearing nodes is invaded or adherent and requires excision, an elliptical incision is made around the involved skin and then extended medially and laterally.
      • In this setting, the incision may alternatively be extended superiorly from the lateral border of the ellipse and inferiorly from the medial border to make a single S-shaped incision for the iliac and inguinofemoral dissections
• Develop and raise superior and inferior skin flaps (≈6—8 mm thickness) below Camper's fascia.
  • Care should be taken to preserve the superficial blood supply to the flaps, thus minimizing the risk of postoperative skin necrosis, infection, and wound breakdown
  • Camper’s fascia can be preserved and left attached to the overlying skin when the superior and inferior skin flaps are fashioned.
    • Lymphatic drainage of the penis to the groin runs beneath the Camper fascia
  • Important to leave a 6—8 mm thickness of subcutaneous tissue in contact with the skin to avoid necrosis[5]
  • Superior skin and subcutaneous tissue flap is developed ≈8 cm superiorly
  • Inferior skin and subcutaneous tissue flap is developed ≈6 cm inferiorly
  • Handle the skin flap edges gently
    • Avoid grasping of the flap edges with forceps because this could potentially crush and devascularize the tissue.
    • Consider covering skin flap edges with saline-moistened sponges
• Expose the inferior border of the inguinal ligament, spermatic cord, and external oblique aponeurosis
• Lymph node dissection
  • Use titanium surgical clips, absorbable suture, or LigaSure for meticulous control of lymphatic channels to avoid a lymphatic leak.[6]
  • Superficial lymph node dissection
    • Remove lymphatic tissue above the fascia lata
      • Fascia lata is continuous with Scarpa fascia superiorly, transitions at inguinal ligament
    • Majority of the lymph nodes will be found in the central and medial zones[7]
      • In obese patients, it may be easy to overlook the superior medial zone nodal tissue if a prominent suprapubic fat pad is present.
    • Superior boundary: dissect the fat and areolar tissues from the external oblique aponeurosis and the external ring/spermatic cord to the inferior border of the inguinal ligament
      • The first lymphatic packet extends from the base of the penis to the superomedial portion of this lymph node package[8]
      • A funiculus of lymphofatty tissue, extending from the base of the penis to the superomedial portion of the lymph node packet, is ligated and divided.
    • Inferior boundary: inferior angle of the inguinofemoral exposure at the apex of the femoral triangle
      • At the inferior boundary, the Great saphenous vein is identified
        • In traditional standard radical inguinal lymphadenectomy, the Great saphenous vein is ligated and divided. However, this increases the risk of lower-extremity complications and in patients with minimal metastatic disease, it may be feasible and beneficial to spare the saphenous vein.
        • In modified inguinal lymphadenectomy (see below), the Great saphenous vein is spared.
    • Medial boundary: Dissect medially to identify the aponeurosis of the adductor longus muscle of the thigh
    • Lateral boundary: Dissect laterally to identify the aponeurosis of the sartorius muscle
  • Deep lymph node dissection
    • To harvest the deep nodes, the fascia lata is entered at the level of the fossa ovalis[9]
    • The nodal dissection is done from inside to outside until the femoral vein is identified whose medial side must be completely exposed[10]
      • The anterior aspects of the femoral vessels are dissected, but the femoral vessels are not skeletonized, and the lateral surface of the femoral artery is not exposed.
        • This avoids injury to the femoral nerve and the deep femoral artery
          • The femoral nerve is usually not visible as it runs beneath the iliacus fascia lateral to the femoral artery.
          • Branches of the femoral nerve can be on the lateral border of the femoral artery, which must be preserved.
    • Use both blunt and sharp dissection to resect the deep inguinal nodes.
    • The deep nodes are typically no more than 3–5 lymph nodes contained within the femoral sheath[11]
      • The node of Cloquet is the most proximal and considered the margin between the inguinal and pelvic lymph nodes[12]
    • In standard radical inguinal lymphadenectomy, the saphenous vein is divided at the saphenofemoral junction
    • Continue dissection superiorly along the anterior surface of the femoral vein and the femoral artery up to the inguinal ligament to include the deep inguinal nodes, working medially to laterally over the femoral vein and artery until the femoral canal is reached.
      • Superficial cutaneous perforating arteries are ligated as they are encountered on the surface of the femoral artery.
  • Dissect the femoral canal
    • The femoral canal is located medial to the femoral vein below the inguinal ligament
    • Cloquet’s lymph node is removed.
  • Sartorius flap, if needed
    • If a deep dissection is required and coverage over the femoral vessels and nerves is needed, the sartorius muscle can be transposed as rotational flap by releasing its attachments from the ASIS, providing myocutaneous coverage over the femoral vessels and nerves
      • The sartorius flap is sutured to the inguinal ligament superiorly with interrupted 2-0 Vicryl sutures, and its margins are sutured to the muscles of the thigh immediately adjacent to the femoral vessels
• Intraoperative frozen section has been shown to have diagnostic value in determining the need to proceed to a radical dissection[13]
  • It may be time-saving to proceed to the contralateral dissection while awaiting frozen section results.
• Closure
  • Primary closure of the inguinofemoral dissection is usually possible with minimal or no further mobilization of the excision margins.
    • When circumstances demand a large area of inguinal soft tissue sacrifice, primary closure may be obtained by scrotal skin rotation flaps an abdominal wall advancement flap or a myocutaneous flap based on the rectus abdominis or tensor fasciae latae for more extensive defects.
  • Multiperforated closed-suction drains (10 or 15 French) are placed under the subcutaneous tissue in the dissected area along the femoral vascular axis[14] and brought out inferiorly, to prevent lymphocele formation.
  • Suture skin flips to the surface of the exposed musculature to decrease dead space.
    • This can minimize the risk of a postoperative fluid collection (i.e., seroma) that may serve as a potential source for infection.
  • Reapproximate subcutaneous tissues with 2-0 Vicryl
  • Reapproximate skin with 3-0 non-absorbable suture or skin staples[15]

Modified complete inguinal lymphadenectomy

• Key aspects of the procedure are (5):
  1. Shorter skin incision
  2. Limiting dissection by excluding the areas (2)
     1. Lateral to the femoral artery[16]
        • Lateral limit of dissection is femoral artery modified dissection, compared to sartorius muscle in standard inguinal lymphadenectomy
     2. Caudal to the fossa ovalis[17]
        1. Also known as the saphenous opening[18]
        2. An oval opening in the upper mid part of the fascia lata of the thigh
        3. allow the passage of the great saphenous vein
        4. Lies 3–4 cm below and lateral to the pubic tubercle and is about 3 cm long and 1.5 cm wide.
  3. Preservation of the saphenous vein[19]
  4. Elimination of the need to transpose the sartorius muscle[20]
  5. Thicker skin flaps
• Advantage
  • Less morbidity than standard radical inguinal lymphadenectomy
• Modified dissection should be converted to a radical inguinal lymphadenectomy if positive inguinal lymph nodes are present on frozen section[21]

Step by step

• Similar to standard inguinal lymph node dissection with the following adjustments
  • Incision: 10-cm[22] skin incision is made ≈1.5-2 cm below the inguinal crease
• The saphenous vein is identified and preserved, although a number of branches draining into it will need to be sacrificed.

Post-operative care

• Ambulation is strongly advised immediately after surgery
  • Bed rest for 2 or 3 days is only used if myocutaneous or other large skin flap is used.
• Efforts to minimize lymphedema during the initial postoperative period include applying thigh-high elastic wraps or stockings and elevating the foot of the bed.
• Closed-suction rains are removed after when drainage is <30-50 mL/day for consecutive days which typically occurs 3–17 days following surgery[23]
• Sutures and/or staples are removed on Day 15[24]
• A suppressive dose of a cephalosporin for 1 to 2 months may be used until healed to decrease the incidence of erythema and cellulitis, and this seems to improve overall wound healing.

Adverse Events

• Wound infection
• Skin flap necrosis
• Wound dehiscence
• Hemorrhage
• Seroma or lymphocele
• Lymphedema, debilitating lymphedema
• DVT
• Sepsis
• Complication rates reported to be as high as 50%[25]
  • Methods to reduce complications (4)
    1. Meticulous usage of clips, instead of electrocautery, to ligate lymphatic channels
    2. Inguinal pressure dressings
    3. Antibiotic regimens
    4. Stockings
• Strong risk factor for complications is palliative indication for ILND§

Minimally Invasive Inguinal Lymphadenectomy

• The morbidity of an endoscopic inguinal lymph node dissection is lower than previously reported for open contemporary series with a similar number of nodes being harvested

Questions

1. What part of the penis is drained by the superficial vs. deep lymphatic system?
2. What are the boundaries of dissection in inguinal lymph node dissection?

Answers

1. What part of the penis is drained by the superficial vs. deep lymphatic system?
2. What are the boundaries of dissection in inguinal lymph node dissection?

References

• Hinman’s Atlas of Urologic Surgery, 4th Edition Joseph A. Smith, Jr., Stuart S. Howards, Glenn M. Preminger, Roger R. Dmochowski
• Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, vol 1, chap 39
• Leone, Andrew, et al. "Contemporary management of patients with penile cancer and lymph node metastasis." Nature Reviews Urology 14.6 (2017): 335-347.