Статьи

Ultra-low levels of local anesthetic in sentinel lymph node excision
Introduction

In cases of malignant melanoma with a tumor thickness in excess of 1 mm, excision of the primary draining lymph node in the lymphatic drainage pathway is currently considered the appropriate guiding standard for advanced tumor staging. These procedures are frequently conducted with tumescent local anesthesia, and not uncommonly with general anesthesia as well.
Our studies have revealed that astoundingly low amounts of infiltration local anesthesia may also suffice.


Method

In our clinic, we use a uniform standard procedure to conduct all sentinel lymph node excisions. After radionuclide labeling and skin demarcation by visualization with a gamma camera in the nuclear medicine department, patent blue staining is completed in the OR. Localization of the lymph node is verified by means of a gamma probe (Gamma Finder® II), and then the incision is plotted. Depending on the localization, a straight or crescent-shaped line of approximately 5 to 10 cm in length is typically applied. Intradermal infiltration of a buffered 1% Xylocaine solution with adrenaline is then administered along the line of the drawing. The amount of local anesthetic is between 3 to 5 ml. The scalpel is applied directly thereafter. After preparation, predominantly by means of surgical scissors and the insertion of a spreader, the blue-stained lymph node comes into the field of view and located with a gamma probe. If there is pain sensitivity, targeted infiltration can be accomplished in the deeper regions. The total amount of local anesthetic did not exceed 8 ml in any of the last 10 patients studied (8x axilla, 2x inguinal). Upon request, the patient may be given an oral dose of 1 mg Lorazepam (Tavor®) prior to surgery. Additional analgesics are not necessary.


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Example of a primary tumor excision site, seen here in the upper back (figure 1). Detailed view of methyl-blue staining (figure 2) and marking of the lymph node in projection on the skin (figure 3). Depiction of findings using a gamma camera (figure 4).

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Examples of intraoperative detection of the sentinel lymph node using Gamma Finder® II (figure 5) and meticulous preparation (figure 6). Verification of a removed sentinel lymph node (figure 7) and site preparation after completion of the procedure (figure 8).


Discussion

A major advantage to the use of local anesthetic is the ability to communicate with the patient during surgery. A lucid patient is hence able to provide an active functional control, for example, for procedures in proximity to the nerves of the extremities. Moreover, postoperative risks are minimized, since the patient is conscious, breathing spontaneously, and remains mobile. We find that commonly used tumescent local anesthesia is more expensive without providing any additional benefits, and can therefore be dispensed with. Based on our experience, pain sensitivity in the subcutis is minimal. Except for the extensive distention, contact with the nerves, or injury to larger innervated vessels, and when manipulations take place in direct vicinity of the lymph node, patients expressed no pain. The inability of the patient to sustain a specific position during procedures into the axilla that are longer in duration may be more problematic than localized pain. Local anesthetic procedures are only unsuited if patients are experiencing fear or are uncooperative.


Summary

Based on our experience, one can also conduct lymph node removal in the axillary and inguinal regions using very small amounts of an infiltration, anesthesia without complication and with greater safety to the patient.
Conclusion: Less anesthesia also works well.

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