Block dissection of the inguinal lymph nodes

Squamous cell carcinomas of the skin of the leg, and the penis, both metastasize to the nodes of the groin. Removing these metastases in a block of tissue, containing the horizontal and vertical inguinal nodes, can be very successful, because these carcinomas are not very malignant.

The femoral vein, artery, and nerves lie close to the nodes that need to be removed, and may be displaced by them. Removing them without damaging these structures is a difficult, delicate, major operation. Afterwards, the wound can discharge tissue fluid and become secondarily infected. Healing may be delayed, the flaps may necrose, and lymphoedema may develop in the patient's legs (5[nd]10%). For all these reasons, refer him if you can. If you have to remove his inguinal nodes yourself, study the anatomy thoroughly before you start, and dissect them away carefully. Blood loss is usually not great[md]provided you don't damage major vessels!

If his inguinal nodes are involved clinically, remove them at the same time that you amputate his leg, or his penis, because he may refuse a second operation. Don't try to remove them prophylactically, in the hope of removing metastases which you cannot feel. It will not improve his prognosis, and may be complicated by lymphoedema (31.4). Only do a block dissection therapeutically, when his lymph nodes are palpably enlarged by secondary growth. If infection is likely to be the cause of the enlargement, wait for it to improve after the amputation, and watch him regularly. Do a block dissection if his nodes start enlarging.

Block dissection of the nodes of the neck is not described here. Removing them from the axilla is described as part of Patey's operation for carcinoma of the breast (21.6).

Fig. 32-20 BLOCK DISSECTION OF THE INGUINAL LYMPH NODES. A, a ''T' incision. B, a ''lazy S' incision. C, reflect superior and inferior flaps. D, prepare to reflect a triangular block of tissue. E, reflect a block of tissue medially from the femoral vessels. F, tying the saphenous vein.

BLOCK DISSECTION [s8]OF THE INGUINAL NODES INDICATIONS. (1) Clinical involvement of the inguinal nodes, with secondary deposits from squamous cell carcinoma of the penis, or leg. If a patient's nodes have not ulcerated, removing them may cure him. If they have ulcerated, you may be unable to remove the mass of ulcerated tissue completely. The determining factor is whether or not they have stuck to deeper structures, especially the femoral vessels. (2) Malignant melanoma; block dissection is often only palliative, but is not always so. His nodes may be large and ulcerate. Don't wait for them to do this before you operate, because they may be impossible to remove later. His prognosis is much worse than with squamous cell carcinoma, because he may already have secondary deposits elsewhere.

If he also requires an amputation, say below the knee for a squamous carcinoma, do both operations at the same time; he may not consent to another one. If you are also going to amputate his penis, make the incisions in continuity, and do both sides at the same time.

CAUTION ! This is a difficult operation, so refer him if you can.

HISTOLOGY. Make the decision to operate clinically, and don't take a node for biopsy first. If you think that nodes really are malignant, don't let the biopsy report influence your decision[md]a malignant deposit in a node may have been missed histologically, or it may only be in other nodes. After the operation, send a node which you think has metastases, and the nearest node to the femoral canal. If you can easily dissect out Cloquet's node in the femoral canal, send that; but if removing it might endanger the femoral vein, leave it.

ANAESTHESIA. General anaesthesia with spontaneous respiration (A 11.1), or subarachnoid (spinal) anaesthesia (A 7.1). Have 2 units of blood ready.

METHOD. Lay him supine with a sandbag under the buttock of his affected side. When you have completed one side, move it to the other one.

Make a ''T' or ''lazy S' incision (A, or B, in Fig. 32-20). A ''lazy S' incision allows you to remove skin, and produces the least skin necrosis, but finding your way may be more difficult. Here, we assume you have decided to make a ''T'incision.

Make the horizontal limb of the ''T' 2 cm distal to his inguinal ligament, 8 to 10 cm long, centred just distal to his mid-inguinal point, where you can feel his femoral pulse. If some skin needs removing, keep away from the diseased area, and cut an ellipse round it, so that you can excise it with the lesion.

Reflect the superior flap with about 0.5 cm of subcutaneous fat, and undermine it 5 cm above your incision. Use a knife or scissors to dissect upwards under it, until it is about 5 cm wide.

At the upper extremity of the flap divide the subcutaneous tissues covering his abdominal muscles in the depth of the wound. Reflect a block of subcutaneous tissue downwards (C), until you reach his inguinal ligament. Don't cut his cord. Clamp, divide, and tie the vessels as you go.

Make the vertical limb of the ''T' 8 to 10 cm long, from the mid point of the horizontal limb, distally over the mass of nodes[md]unless you need to remove some skin. If so, make it elliptical.

Dissect out flaps of skin with 0.5 cm of subcutaneous tissue, as far as is easy, to expose a triangular block of tissue laterally, medially, and distally. Make its apex at least 4 cm distal to any palpable node. Cut through the subcutaneous tissues at the edges of the triangular mass, down to the deep fascia or muscle (D). As you do so, find and clamp his saphenous vein. Tie it with No. 0 silk. Its surface marking is a line from just medial to his mid-inguinal point to the medial aspect of the medial condyle of his femur. Avoid his femoral vessels, which lie 2 or 3 cm lateral to his saphenous vein near the distal end of the incision. Dissect down with scissors, looking for the vessels, which are covered by a sheath. The femoral vein lies posteromedial to the femoral artery, and is largely covered by it at this point, and by the strap-like sartorius muscle. Tie and divide any smaller vessels you meet.

Dissect the block of tissue proximally from the apex of the wound. As you do so, remove it from the femoral vessels, for about 3 cm. Retract it with tissue forceps. Reflect medial and lateral flaps, in the same way as the superior one, as far out as you can retract them comfortably. Then clear the block of tissue from the underlying muscles. On the lateral side, you will meet his femoral nerve proximally. Continuing to work from distal to proximal, reflect the block of tissue from his femoral vessels medially (E). Tie and divide any small vessels you meet, close to the main ones.

CAUTION ! (1) Pulling on the block of tissue may pull up his femoral vessels, so you may think that his femoral vein is his saphenous vein. Don't clamp, divide, or damage his femoral vein, which may become flat and empty as you pull on the tissues. (2) Try not to damage his profunda femoris or circumflex vessels (medial and lateral), which pass deep to the muscles of his thigh.

Continue to dissect proximally. This is the difficult part. Find where his saphenous vein (which may be flat and empty) joins his femoral vein. About 1 cm distal to the junction it receives several tributaries (the superficial circumflex iliac, the superficial epigastric, and the superficial external pudendal veins). When you are sure you have found it, use an aneurysm needle to pass two No. 0 silk ligatures under it, at least 5 mm apart (F). Divide it between these ligatures[md]away from the femoral vein!

The block of tissue will now be almost clear, with nothing important attached to it. Dissect it free. Suture his sartorius muscle over his exposed femoral vessels; this is readily possible in the distal part of the wound[md]don't leave them exposed, or they may ulcerate and bleed disastrously.

If you can obtain good skin closure, and the wound is airtight, insert a suction drain (if you have one), with its limbs medially and laterally. If you don't have a suction drain, or the wound is not airtight, insert corrugated rubber drains through 1.5 cm incisions medially and laterally.

Close the skin flaps with No. 0 or No. 1 interrupted monofilament sutures. Apply a cotton wool pressure dressing for 48 to 72 hours. Shorten the corrugated drains on the third day. Remove alternate sutures on the 12th day, and the others when the wound seems sound.

Now, if you are operating for carcinoma of the penis, do the same thing on the other side.

DIFFICULTIES [s7]WITH BLOCK DISSECTION OF THE INGUINAL NODES Infection and necrosis of the skin edges are common. Complete healing takes time, but does occur.

If you INJURE A FEMORAL VESSEL, usually the vein, press it to control bleeding, then clamp it above and below with artery forceps covered with suitable pieces of rubber catheter, or, better, use forceps specially designed for vascular surgery (55-4). If possible close the hole in the vessel as in Section 55.6, then remove the clamps.

If you cannot control bleeding, tie the vein above and below the wound. His leg will swell, but will usually improve in time. It is rare for it to become gangrenous and be lost.

If you cannot CANNOT COVER HIS FEMORAL VESSELS with his sartorius muscle proximally, separate it at its origin from his anterior superior iliac spine. Suture it to the fascia of his external oblique just proximal to his inguinal ligament in such a way that it covers his femoral vessels.

If CLOSURE OF THE WOUND IS DIFFICULT, don't close it under tension. If there is suitable muscle in the bare area, apply a split skin graft immediately and suture it in place using a gauze stent (57-7). Or, take a graft now, store it, and apply it 5 days later (57.8). If his femoral vessels are exposed, mobilize his sartorius, as described above.

If he develops LYMPHOEDEMA, he is one of the unlucky 10% of patients who do. Advise him to raise his leg at night, and prop it up when he sits. If possible apply an elastic bandage, or as a poor second best, a cr[ci]epe one.