I had my neck dissection 3 weeks ago today,in addition to surgery on my tongue tumour.I got the impression from my surgeon that a ND was standard practice concerning tumours such as mine under the tongue (mine was stage 2).
I had the CT and MRI scans and nothing untoward showed up on them.However, I had zones 1 to 4 removed during my dissection and 3 of the 30 nodes removed were found to be cancerous,one having burst throught the capsule.
The incision is large and slightly shocking when you first see it - but that 'shock' soon passes and my scar is now healing very well.It's a little tight in terms of movement but my Physio/excercise should alleviate that.I didn't endure much pain at all - so if an ND is needed,it's certainly manageable if that's any consolation.I had 2 drains in my neck for about 5/6 days and they do restrict your movement - removal of one of these made me wince a little,but that was momentary and as my wife says I'm probably getting a bit soft as the years pass.
I've got my 6 week stint of radiotherapy and chemotherapy starting in about a month, so my treatment seems to be the other way around.Doctors eh?

Good luck - I hope it all works out for you both.