Preserving The Submandibular Gland

As already mentioned, removal of the submandibular gland is not a routine surgical step of functional neck dissection. The gland must be included in the specimen when the location of the primary tumor dictates its removal or when metastatic disease is suspected in the submandibular triangle. In the remaining situations the submandibular gland may be preserved. This is the case with cancer of the larynx and hypopharynx, where the lymph nodes in the submandibular and submental region (area I) are usually not involved and, additionally, there is no need to approach the primary tumor through the submandibular triangle. When a submandibular gland preserving functional neck dissection is performed, the dissection of the upper border of the surgical field must be modified with respect to the procedure described in the previous chapter.

After the flaps have been raised, the submandibular gland can be seen through the superficial layer of the cervical fascia in the upper part of the surgical field (Fig. 5-9). The fascia is then incised from the midline to the tail of the parotid gland, at the level of the lower border of the submandibular gland as for a gland-removing procedure. Then the facial vein is ligated and divided, reflecting upward the superior ligature to preserve the marginal mandibular branch of the facial nerve. The retromandibular vein and the external jugular vein are also ligated and divided.

I F

mn

SG

fc"\ - f - r "

PG

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Figure 5-8 Protection to the marginal mandibular branch of the facial nerve is obtained with the maneuver of the facial vein (right side). fv, facial vein; mn, marginal nerve; F, fascia retracted upwards; SG, submandibular gland; PG, parotid gland.

Now, instead of including the submandibular gland within the specimen, its fascia is dissected inferiorly while the gland is retracted superiorly (Figs. 5-10 and 5-11). The contents of the submandibular fossa are now exposed. The fibrofatty tissue containing the submandibular nodes is grasped and dissected off the submandibular triangle, preserving the gland. The dissection may be continued medially to include the submental nodes, but this is seldom required in tumors that allow preservation of the submandibular gland.

Figure 5-9 Lateral view of the surgical field after elevation of the skin flaps, preserving the deep layer of the cervical fascia (right side). SG, submandibular gland; SC, sternocleidomastoid muscle; tc, transverse cervical nerve; SF, superior skin flap; Erb's point.
Figure 5-10 The fascia is incised in the upper boundary of the surgical field and dissected inferiorly over the submandibular gland. SG, submandibular gland; SC, sternocleidomastoid muscle; F, fascia dissected inferiorly.

The dissection then continues over the digastric and stylohyoid muscles. The muscles are retracted superiorly (Fig. 5-12), and the fascial sheath is easily dissected from the subdigastric and upper jugular spaces. The hypoglossal nerve is identified and the dissection is continued in the usual way, the only difference being the preservation of the submandibular gland.

Figure 5-11 The submandibular gland is retracted superiorly, exposing the digastric muscle. SG, submandibular gland; SC, sternocleidomastoid muscle; it, intermediate tendon of the digastric muscle; fv, facial vein.
Figure 5-12 Retraction of the submandibular gland and digastric muscle allows the dissection of the submandibular fossa (right side). SG, submandibular gland; it, intermediate tendon of the digastric muscle; hn, hypoglossal nerve; lv, lingual vein.
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