Appendix 2: overview of surgical techniques.
Conventional approach: (Iaremenko (6)): An incision is
made in the upper third part of the lateral neck, along a skin crease.
Usally 2,0-2.5 below the lower border of the mandibule. Incision is made
trough the subcutaneous tissue, the fascia superficialis, platysma
muscle. External jugular vein is transected and ligated. Fascia media
and fascia profunda are dissected. Cyst fluid aspiration is performed if
required. Cyst is removed in total. The wound is closed layer by layer
using biodegradable sutures. Drainage tube is placed. The wound is
covered with a tight aseptic dressing.
Retro auricular hairline approach (Chen 2009 (11)): Retro
auricular incision was made through the skin, subcutaneous tissue, and
platysma
muscle. The incision was made along the post auricular sulcus and
hairline, starting from the lower end of the post auricular sulcus,
moving upward to the middle or upper third of the sulcus, and then
smoothly angulating downward to 0.5 to 1 cm under the hairline. Careful
attention to the overlying sternocleidomastoid muscle prevented injury
to the great auricular nerve. The skin flap
was elevated just above the sternocleidomastoid muscle onto the carotid
triangle. The cysts were exposed anterior and deep to the
sternocleidomastoid muscle at the level of the carotid bifurcation. Dull
dissection was used to free the attachments of the cysts. The cysts were
then completely removed after aspirating luminal contents. All of the
cysts were separated easily from the surrounding
normal tissues and removed completely using this approach without tumor
spillage. The retro auricular skin flap was repositioned and sutured.
Endoscopic lateral neck approach (Chen 2014(9)): A lateral
neck incision was made in the skin, subcutaneous tissue, and platysma
muscle. The incision was made along the skin line below the lower bound
of the cyst. The working space was created by elevating the skin flap
with self-designed custom-made retractors to establish a stable
operative space. The wound margin was protected by two applications to
avoid injury from the ultrasonic scalpel. Dissection using the
ultrasonic scalpel was performed to free the attachments of the cyst.
When we separated the cyst, we took care to avoid impairing the common
carotid artery, internal jugular vein, vagus nerve, hypoglossal nerve,
and accessory nerve. The cyst was completely removed. For very large
cysts (longest diameter
of 7 cm) decompression was often performed by fluid aspiration and
needle pricking.. The wound was closed by a subcuticular suture with 4-0
Dexon, and a small ventricular drainage tube was inserted.
Endoscopic RAHI: (Chen 2012 (10)): A retroauricular incision was
made through the skin, subcutaneous tissue, and platysma muscle. The
incision was made along the postauricular sulcus and hairline, starting
from the lower end of the postauricular sulcus, moving upward to the
middle or upper third of the sulcus, and then smoothly angulating
downward to 0.5 cm above
the hairline. The skin flap was dissected under platysma with the help
of the 4-mm-diameter endoscope. During this step, careful attention to
the overlying sternocleidomastoid muscle prevented injury to the great
auricular nerve and external jugular vein. The working space was then
produced by elevating the skin flap just above the sternocleidomastoid
muscle onto the carotid triangle. The cyst was exposed anterior and deep
to the sternocleidomastoid muscle at the level of the carotid
bifurcation after carful dissection of the accessory nerve and posterior
belly of digastric muscle. Then, dissection using the ultrasonic scalpel
was carried out to free the attachments of the cyst, and the cyst was
completely removed. In very large cysts (longest diameter 8 cm),
decompression was often performed by fluid aspiration and
needle-pricking. Finally, the wound was closed by subcuticular suture
with 4-0 Dexon, and a small Hemovac was placed for drainage.