Parotidectomy : Operative Technique

Describes in detail about the steps, types and complications of the surgery.

1. Operative Technique : Parotidectomy By: Dr Sangamesh S K Mod: Col VP Singh

2. Contents Introduction Embryology Surgical Anatomy Types of parotidectomy Procedure Complications

3. Introduction Parotid is the largest salivary gland Pre auricular region both sides of cheek Weighs : 15-30 gms 2 lobes: superficial and deep Divided by facial nerve traversing within Accessory parotid gland may be present

4. Embryology 6 to 8 week : Outpouching of oral ectoderm As it grows posteriorly, facial nerve advances anteriorly toward midline Facial nerve becomes surrounded by glandular tissue Lymph nodes are encapsulated by mesenchymal capsule : Iintraparotid lymph node

5. Surgical anatomy It lies in a recess bounded by ramus of mandible, base of skull and mastoid process It lies on carotid sheath, CNs XI and XII and extends forward over the masseter muscle

6. Capsule Enclosed in a sheath of dense deep cervical fascia Its upper pole extends just below the zygoma and its lower pole (tail) into the neck

7. Surgical relations Posterior: Cartilage of EAC Tympanic bone Mastoid process SCM muscle Deep: Styloid process Stylomandibular tunnel Parapharyneal space Superior: Zygomatic arch TMJ

8. Structures running in parotid

9. Structures running in parotid ● Facial nerve trunk : divides into its major five branches ● Terminal branch of External carotid artery : divides into maxillary & superficial temporal artery ● Retromandibular vein ● Intraparotid lymph nodes. Gland is arbitrarily divided into deep and superficial lobes: by facial nerve. 80% : superficial and 20% : deep to the nerve.

10. Facial nerve & branches

11. Autonomic nerve supply

12. External Carotid Artery & Retromandibular Vein

13. Stenson duct Runs over masster muscle anteriorly and downwards Turn inwards pierce Buccal pad of fat Buccopharyngeal fascia Buccinator muscle Opens opposite 2 nd maxillary molar teeth Accessory lobe is occasionally present Along duct on masseter muscle

14. Types of parotidectomy Partial parotidectomy: Resection of pathology with a margin of normal parotid tissue (1cm) Benign pathology & low grade malignancies Superficial Parotidectomy: Entire superficial lobe resection Mets to parotid lymph node e.g from skin cancers and high grade malignant parotid

15. Types of parotidectomy Total parotidectomy: Resection of entire parotid gland Preservation of facial nerve Radical parotidectomy Superficial & deep parotid gland Extended to involve adjacent structures

16. Position Patient in 45 reverse trendelenburg position with head higher than heart Head turned to opposite side of lesion Neck extended by rolled sheet below chest and doughnut pillow head Ipsilateral shoulder : corner of bed Surgeon : Ipsilateral gland to be dissected Assistant : at head & opposite the surgeon Scrub technician : side of surgeon

17. Draping Sterile scrub Ipsilateral visible Ear Lateral corner of eye Oral commisure Entire ipsilateral neck

18. Incisions Modified Blair incision or lazy S incision Initially “L” shaped incision Bailey modified with cervical extension Exposes : posterior part and tail of parotid

19. Incisions Y Shaped incision

20. Flaps raising : anterior extent Skin flap developed : anterior border of gland Anteriorly flap is raised till terminal branches of facial nerve visualised

21. Posterior extent of dissection Greater auricular nerve & facial vein are identified, ligated & divided to expose : tail of the parotid and SCM muscle Posterior belly of digastric muscle is exposed beyond its attachment to temporal bone

22. Superficial Muscular Aponeurotic System (SMAS) Fibrous network that invests facial muscles, & connects them with dermis Platysma inferiorly Z ygomatic Arch Superiorly Facial nerve courses deep to SMAS & Platysma Parotid fascia

23. Techniques : Identify Facial nerve Antegrade : Inferior portion of the cartilaginous canal, Conley’s pointer - Tragal pointer : lies 1 cm deep & inferior Upper border of the posterior belly of the digastric muscle : mobilise the parotid gland, & exposes an area superior : nerve lies here Squamotympanic fissure Styloid process (the nerve is superficial to it) Mastoid process can be drilled and the nerve identified more proximally Retrograde : Any branch is identified and traced back till trunk

24. Identifying facial nerve Next the fascial attachments between EAC & parotid tissue divided to identify : Tragal pointer Using the following landmarks the main trunk of the facial nerve can be identified

25. Facial nerve mobilization No tissue is cut in this area until the nerve is seen. Blunt dissection proceeds posterior to anterior until the surgeon identifies the nerve as a white cord 2–3 mm wide Meticulously elevate parotid tissue off nerve blanches Bipolar cautery used near nerve Parotid tissue overlying the nerve is then divided

26. Branching of facial nerve Nasser Nasse , British Journal of Oral and Maxillofacial Surgery, Volume 54, Issue 10, December 2016, Pages e61-e6

27. Superficial parotidectomy Faciovenous plane of Patey developed Duct is ligated and divided

28. Deep parotidectomy Small vessels around deep gland adjacent to mastoid & trunk cauterized : bipolar cautery If needed extend incision : neck dissection

29. Facial nerve sacrifice If facial nerve function is normal preoperatively, even malignancy : nerve can be preserved with careful dissection If nerve is paretic or fully paralyzed preoperatively : resected during tumor resection. Invaded by high-grade malignant tumor : resected with specimen to negative margins. Peripheral branches, divisions, or even main trunk of facial nerve may be sacrifice Intra- op nerve if infiltrated appears swollen & usually darker than normal glistening white appearance

30. Repair Primary neurropahy or grafting Mastoidectomy and nerve mobilization : length & free tension Grafts Ipsilateral Greater Auricular nerve Ipsilateral Sural nerve graft Proximal facial nerve Ipsilateral cranial nerve XI XII

31. Radical parotidectomy Radical parotidectomy : histological evidence of high-grade malignant tumour with facial nerve invasion (e.g. squamous cell carcinoma) All parotid gland tissue Elective division of the facial nerve, usually through the main trunk Surgery inevitably removes ipsilateral masseter muscle May also require simultaneous neck dissection Particularly if clinical, radiological and cytological evidence of lymph node metastases in the ipsilateral neck

32. Complications Hematoma Facial nerve palsy Salivary fistula Gustatory sweating/ Frey’s syndrome Cosmetic deformity

33. Hematoma Inadequate haemostasis before closure Suction drain reduce post op hematoma Treatment Evacuation of hematoma

34. Facial nerve palsy Temporary or permanent Partial or total Neuropraxia : nerve stretching If nerve intact: recovers with in weeks

35. Facial nerve palsy… If palsy severe and recovery prolonged: transcutaneous nerve stimulation of facial muscles Problems with eye closure : exposure keratitis Protective glasses or tape of eyelid Temporary tarsorrhapy Botulin toxin paralysis of upper eyelid When palsy : total loss of facial nerve Reconstruction & Rehabilitation of face

36. Salivary fistula Presents at suture line, post to ear lobe Pressure dressing Drains Anticholinergic drugs

37. Cosmetic deformity Sunken cheek due to loss of parotid gland and fat Rotation of SCM muscle flap Free flaps

38. Frey’s syndrome Damage to autonomic innervations of salivary gland Inappropriate regeneration : Postanglionic parasympathetic nerve fibres of auriculotemporal nerve Aberrantly stimulate the sweat glands of overlying skin Clinical features include sweating and erythema (flushing)

39. Cause of Frey’s syndrome Parasympathetic and sympathetic secretomotor stimuli Misdirected to cholinergic receptors of sweat glands during healing

40. Iodine test Alcohol-iodine- oil solution : starch powder Dry : lemon candy for 10 min

41. Treatment of Frey’s syndrome No effective treatment, Various options Injection of botulinum toxin Surgical transection of nerve fibres Application of ointment : anticholinergic drug such as scopolamine

42. Thank you