can happen [15], and patients need to be warned
about this. In most cases this gradually disappears
with time but occasionally it leads to permanent
tattooing of the skin (Fig. 2).
Rodier and Janser report an anaphylactic reac-
tion as a result of administration of the patent blue
dye in one patient in a study of 65 patients [15].
Probe-Guided Surgery
The success rate of gamma detection probe-guided
surgery is superior to that of blue dye mapping
alone [7, 8, 16]. As already mentioned, the experi-
ence of Albertini et al. [7] indicates that the addi-
tion of a gamma detection probe increases the
success rate of sentinel node localisation from 73%
to 92 %.
Knowledge of the location of the sentinel node
before surgical exposure is what differentiates
probe-guided surgery and lymphatic mapping [5,
17, 18]. The site of the sentinel node is identified
even before the incision is made. Another impor-
tant advantage of probe-guided surgery is that
complete excision of the sentinel nodes can be
verified by directing the probe into the wound to
measure the residual activity.
Vari ous reports suggest that combination of
blue dye lymphatic mapping and probe-guided
sentinel node localisation is advantageous [7, 16,19,
20]. The overall success of sentinel node localisa-
tion is maximised and the incidence of false-nega-
tive results reduced when both techniques are used
in conjunction. This is because a probe will give
Blue Dye Lymphatic Mapping
With the intraparenchymal injection of the blue
dye alone, the success rate for identification of the
sentinel node varies between 65% and 93 %,with a
reported false-negative rate of 0% –12% [9, 10].
The lymphatic mapping technique with blue dye
can be tedious and a significant training element
is involved [11]. The extent of the dissection and
disruption of lymphatic channels can be higher as
compared with probe-guided surgery; moreover,
localisation of sentinel nodes in lymphatic basins
other than the axillary basin is not possible
[12–14].
Timing of injection of the blue dye is crucial for
the success of the procedure. If it is injected too
early, there would be extensive blue staining of
lymph nodes in the nodal basin,making the task of
sentinel node localisation impossible.On the other
hand if the injection is administered too late, suc-
cessful localisation may fail owing to the inability
of the dye to reach the sentinel node because of
inadvertent disruption of the lymphatic channels
during dissection. It seems that the optimal time
for injection of the blue dye is approximately 5 min
prior to the surgical incision, and we have had
satisfactory results in this way.
The reported side-effects associated with the
patent blue dye include cutaneous rash, observed
in particular in patients with a previous history of
allergic reaction. Blue to green discoloration of
urine (Fig. 1) can be a cause for concern to the pa-
tient postoperatively, and this effect needs to be
explained to the patient. Persistence of blue stain
after intradermal injection of the patent blue dye
chapter
7
80
Fig. 1.
Dark blue discoloration of urine due to patent blue dye

injection, 18 h postoperatively

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Fig. 2.
Persistence of blue staining of skin 6 months post-
operatively