Superficial parotidectomy

Gland size esp inferior extent is variable, but main trunk as it enters the parotid is relatively constant.

Separation between deep and superficial lobe is arbitrary

80% of parotid gland parenchyma is lateral to the nerve

Turn head away. Head ring.
Prep to expose ear, lateral corner of eye, corner of mouth and entire ipsilateral neck
45 deg reverse Trendelenburg
Swab in auditory canal
Modified Blair (sigmoid) incision to 2 finger breadths below mandible
Raise flaps with scalpel and rake retractors. Raise flaps to edge of gland but no further anteriorly as facial nerve branches emanate from anterior border. Use tenotomy scissors with spreading action
Masseter muscle fascia is identified
Do not look for Stensens duct at edge of gland as this can injure buccal branches that travel with it
Identify SCM and dissect from posterior margin
EJV and greater auricular nerve should be seen
In most cases will need to divide nerve but don't do it until after it branches as it may be needed as a nerve graft
Separate inferior aspect of gland from SCM and dissect using Kochers on the gland to the level of the lobule of the ear
Assistant puts rake on tragus and dissect parotid from cartilage. Again Kocher on gland for retraction and identify cartilagenous pointer
There will be a small bridge of tissue that will need division between mosquito
After this division, only bipolar should be used
Look for posterior belly of digastric (palpate mastoid for landmarks)
Free parotid, then identify main trunk of facial nerve:

Nerve exits stylomastoid foramen just posterior to styloid process. Nerve enters parotid just anterior to border of mastoid and digastric muscle. Assistant watches for twitching of face. Use a curved mosquito anterior to cartilagenous pointer to divide tissues layer by layer. Nerve is 2-3mm wide. Posterior auricular artery travels posteriorly along digastric muscle. Generally inferior to main trunk of nerve. Do not divide artery until facial nerve identified. Always ligate artery.

Spread along nerve with artery until pes is seen. Work on broad front. Alternatively use tenotomy scissors and right angle for dissection. In general, work from sup to mid portion and inf to mid portion but tailor to tumour.

Venous anatomy is variable.

Nerve is usually superficial to posterior facial vein.

Gland will then be pedicled on duct.

Traction up not anteriorly by assistant an counter traction with sponge by surgeon is important. Avoid making tunnels along nerve

Complications
1.Facial N palsy after superficial parotidectomy
a.Permanent 1%
b.Transient 30-43%
2.Frey’s syndrome
a.Up to 60% but only 20% complain
b.Resolves or improves
c.Persistence can be treated by tympanic neurectomy (Jacobsen’s nerve) which divides the parasympathetic pathway
d.Topical agents can be used
e.Placing a PTFE implant can reduce the incidence to 3% (? Trial)
3.Salivary fistula
4.Hypoaesthesia of ear lobe
a.Due to division of great auricular nerve
5.Neuroma
a.May be due to cut end of above