| Variations
of Minimally Invasive Technique
Radioguided approach. Several other variations
of "minimally invasive" parathyroid explorations have
been described. Some have advocated minimally invasive radioguided
parathyroidectomy. In a retrospective study, a group of patients
with I HPTH who underwent a preoperative scan with Tc-99m sestamibi,
followed by one or both of two intraoperative techniques, parathyroid
localization using a hand-held gamma detector, and/or iPTH assay
were analyzed. In the first group, an 11-mm handheld gamma counter
was used to measure gamma activity in the neck and upper mediastinum.
Intraoperative gamma probe localization was considered to have been
successful if abnormal parathyroid tissue associated with focal
gamma activity was identified. The study clearly demonstrated two
major advantages in the use of intraoperative gamma probe localization:
on one hand, it helps the surgeon in directing the intraoperative
approach, thus limiting the extent of dissection, and on the other
hand, it can be used to confirm the presence of abnormal parathyroid
tissue within a surgical specimen based on identification of focal
gamma activity ex vivo, assisting therefore in a decision to terminate
the procedure. Interestingly, there was an incidental success with
the gamma probe localization following a nonlocalizing sestamibi
scan suggesting that selected patients with non localizing preoperative
scan may still be candidates for successful intraoperative gamma
probe localization of sestamibi-labelled parathyroid tissue. However,
the authors did not advocate the use of the intraoperative gamma
probe in the absence of good-quality preoperative sestamibi scanning.
Furthermore, they stated that "it is unlikely that routine
application of the intraoperative gamma probe to patients with nonlocalizing
preoperative sestamibi scans will be helpful". But they also
noted that an attempt at intraoperative gamma probe localization
is quite reasonable only in highly selected patients who have equivocal
sestamibi scans and are presenting for reoperative neck exploration.
Therefore, for successful operative management of I HPTH gamma probe
localization is the least essential among the three applied technologies
of preoperative sestamibi scintigraphy, iPTH assay and gamma probe
itself (9).
Endoscopic approach is another form of minimally
invasive parathyroidectomy. It uses a surgical telescope, gas insufflation
and needlescopic instruments. Although it is possible, with experience,
to visualize and
|
readily locate the parathyroid adenoma and its anatomical relationship
to the normal ipsilateral parathyroid gland and the other normal
adjacent structures, confident preoperative localization with either
sestamibi scanning, or ultrasound, or both, is also essential to
the endoscopic procedure.
Reported benefits of this approach include smaller
incision, therefore improved cosmesis, good visualization, thus
less risk of injury of the recurrent laryngeal nerve, and less pain
and discomfort.
Since the first report of endoscopic removal
of parathyroid glands in 1996, there have been several complications
including carbon dioxide narcosis, subcutaneous emphysema due to
lengthy carbon dioxide insufflation time, extended operative times,
possible rupture of the adenoma following removal through a small
port, difficult visualization due to bleeding, and operating space
problems (10,11).
ADVANTAGES
The advantages of the unilateral approach are
numerous and include: the avoidance of general anesthesia, an excellent
cosmetic result, and a shorter operating and recovery time making
it feasible as an outpatient procedure. It offers the added advantage
of not disturbing the remaining parathyroid glands, thereby decreasing
the risk of permanent hypoparathyroidism (3). Furthermore, the principle
of performing minimal dissection, when possible, and converting
to conventional neck exploration poses the least possible risk of
complications, including minimal risk to the recurrent laryngeal
nerve and the other normal parathyroid glands. It also makes subsequent
surgery in the region far less complicated than after the bilateral
neck exploration (12).
In a study done in Vanderbilt University by Goldstein
to compare cost, a group of 20 patients who underwent minimally
invasive radioguided parathyroidectomies were compared with 20 similar
patients who underwent a more conventional surgical approach for
I HPTH. Both groups underwent their procedures during a similar
time period, at a single institution, by a single surgeon. Patients
undergoing the "minimalist" approach had operative and
total hospital charges that were only 52% of the charges submitted
for patients undergoing more standard parathyroidectomy (13).
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