Anatomy Atlas and Interpretation of Spine Surgery

22
J.-g. Shi et al.
Identify and ligate the facial vein that runs on the surface
of the submandibular gland.
The submandibular gland is isolated upward to
expose the intersection of the digastric muscle and stylohyoid
muscle.
The digastric muscle and stylohyoid muscle are
retracted toward the mandible to expose the fascia.
The hypoglossal nerve lies slightly inferior and
beneath the digastric muscle tendon and is parallel to
the direction of the tendon. The hypoglossal nerve
should be protected carefully (Fig. 1.27).
Both the posterior belly of the digastric muscle and
the stylohyoid muscle are within the area of operation
in this approach. Surgeons should avoid pulling the lateral
part of the posterior belly of digastric muscle and
stylohyoid muscle with the retractor in order to prevent
damage to the facial nerve.
The hypoglossal nerve is retracted downward.
Bluntly dissect the deep fascia and palpate the carotid
sheath on the lateral.
Retract the carotid sheath laterally and the posterior
pharyngeal constrictor medially to find entrance to the
retropharyngeal space. If fat pad within the retropharyngeal
space is observed, then the exposure has been
done correctly (Fig. 1.28).
The hypoglossal nerve is medial to the vagus nerve
and the internal carotid artery near the angle of mandible.
It runs inwardly in front of the lingual and facial
arteries and innervates the tongue muscles.
The lingual artery and facial artery can be ligated if
necessary. Otherwise they should be retained to help
prevent overstretching of the hypoglossal nerve.
When the esophagus is injured during surgery, suture
and repeat washout should be performed immediately.
The nasogastric tube should be retained for 1 week after
the surgery.
Dissector is used to clean the alar fascia and prevertebral
fascia.
The longus colli muscle is longitudinally bifurcated
in the midline and attached to both sides of the anterior
arch of the atlas (Figs. 1.29 and 1.30).
The longus colli muscle and anterior longitudinal
ligament are subperiosteal dissected toward lateral
sides. This exposes the anterior atlantoaxial spine and
C2 vertebra (Fig. 1.31).
In order to avoid invading the anterior atlantooccipital
membrane, the incision should not exceed the
cranial border of the atlas.
Subperiosteal dissection should be conducted no
more than 15 mm from the atlantoaxial midline to prevent
damages to the vertebral artery.
Mentum
Mentum
hypoglossal
nerve
Intermediate
tendon of the
digastric
muscle
cephalad
hypoglossal
nerve
prevertebral fascia
cephalad
posterior belly of
digastric muscle
Fig. 1.27 Retraction of the digastric muscle and stylohyoid muscle
toward the mandible
Fig. 1.28 Access through the retropharyngeal space to the prevertebral
fascia