Sentinel Lymph Node Biopsy

Anesthesia Implications

Position: Supine, Reverse Trendelenburg, Prone, Left Lateral, Right Lateral
Time: 30-60 min (short)
Blood Loss: Very Low (5-10 ml)
Post-op Pain: Minimal (1-3)
Maintenance Paralytic: Contraindicated

A sentinel lymph node is the first lymph node a malignant cancer is likely to spread to. So, the anesthetic approach and position here really depends on the location of the cancer.

Most often, the biopsy will be done by a general anesthetic approach.

Below are the indications for breast cancer (one of the most common)

Non-depolarizing muscle relaxants – Intentionally AVOID long-acting muscle relaxants/paralytics. Succinylcholine is fine to get the case started, but the surgeon will need the patient to be paralytic-free later in the case. This is because he/she will be working close to the thoracodorsal and/or long thoracic nerve. Use of cautery in the affected area will cause a twitch when getting close to these nerves. Surgeons like the twitch as an indicator that they are close to the nerve.

Typical positioning – The surgeon typically likes the affected side rotated up towards him/her along with reverse trendelenburg.

End of case – The patient may be hand-hoisted to the sitting position at the end of the case to allow application of a chest binder or wrap. Be cautious of having the patient too light as this will be especially stimulating.

Prone Position (general considerations): Maintain cervical neutrality. Keep IV’s out of the antecubital space. The patients arms are typically flexed, which will kink the IV. Eye protection should be used as the prone position heightens the risk of corneal abrasion and/or traction on the globe (which can result in blindness). Check the patients eyes/ears/nose regularly throughout the case to ensure they are free of pressure. Positioning of the leads is typically high on the posterior and posterolateral back (somewhere free of pressure and out of surgical borders). Keep your connections and tubing where you’ll have fast access.

Lateral position (general considerations): If an ETT has been placed, make sure ETT is secure with extra tape.  Unhook anesthesia circuit while turning lateral and be especially careful to keep patient’s head neutral and aligned with body to avoid neck injury. Once lateral, use pillows/blankets/foam headrest to keep the patient’s head in neutral position. The most common nerve injury for orthopedic lateral procedures are neurapraxias of the brachial plexus. These are motor and/or sensory loss for 6-8 weeks due to pressure on the contralateral (dependent) axilla. To prevent this, place an axillary roll under the patient (caudad to the axilla, on the rib cage, and NOT in the axilla). Check routinely to make sure the axillary roll does not migrate into the axilla. If the non-dependent arm is placed on a board, check padding and reposition regularly to avoid radial nerve compression. If a bean bag is employed, check the hard edges to ensure that unnecessary pressure isn’t being put on soft tissues. Pad all dependent bony prominences such as the fibular head (to prevent peroneal nerve injury), and place pillows between the knees and ankles (to prevent saphenous nerve injury). If anterior hip supports are in place, ensure they are properly padded or neuropraxias and/or occlusions of large blood vessels may result.

The surgeon may use a combination of the gamma probe and a blue dye to find and surgically remove the lymph node.