Selective Neck Dissection - Vula - University of Cape Town

Step 2 (Figure 7)54663Figure 7: Recommended surgical steps forsupraomohyoid neck dissectionanterior jugular veins. The contents of thesubmental triangle are resected withelectrocautery up to the hyoid bone. Thedeep plane of dissection is the mylohyoidmuscle (Figures 8, 9).27 41The surgeon next addresses Level Ib of theneck. The fascia (capsule) overlying thesubmandibular gland is incised midwayover the gland and is dissected from thegland in a superior direction in a subcapsularplane so as to avoid injury to the marginalmandibular nerve (Figure 10). Usingthis technique the marginal mandibularnerve does not need to be routinelyidentified; the assistant however watchesfor twitching of the lower lip as this indicatesproximity to the nerve. The marginalmandibular nerve crosses the facialartery and vein (Figure 11).The facial arteryand vein are identified by blunt dissectionwith a fine haemostat (Figure 11).Figure 8: Resection of submental triangleFigure 10: Incision of submandibularsalivary gland capsuleFigure 9: Resection of submental trianglefrom mylohyoid muscleNext attention is directed to the fat andlymph nodes tucked anteriorly betweenthe anterior belly of digastric and mylohyoidmuscle (Figure 11). These nodes areespecially important to resect withmalignancies of the anterior floor ofmouth. To resect these nodes one retractsthe anterior belly of digastric anteriorlyand delivers the tissue using electrocauterydissection with the deep dissection planebeing on the mylohoid muscle (Figures 12,13).4