1. Surgical Approaches to the Oropharynx
Karen Stierman, M.D.
Christopher Rassekh, M.D.
January 13, 1999

2. Anatomy Connects the nasopharynx and oral cavity to the hypopharynx
Extends from hard palate to hyoid
Opens into oral cavity. Bounded by circumvallate papillae, ant. tonsillar pillar, and junction of the hard and soft palate
Clinically significant: lateral and posterior walls, tonsil, base of tongue, soft palate

3. Anatomy(cont’d)
Pharyngeal walls made up of mucosa, submucosa, pharyngobasilar fascia, constrictor m., buccopharyngeal fascia
Lateral walls made up of ant. and post. tonsillar pillars, tonsillar fossa with the palatine tonsil, lateral phayngeal wall
Soft palate made up of palatine aponeurosis, tensor and levator veli palatini, uvular m, palatoglossus, palatopharyngeus

4. Anatomy(cont’d)
Base of tongue extends from the cirumvallate papillae to the pharyngo and glossoepiglottic folds.
Lingual tonsils are on the superficial and lateral surfaces
Irregular surfaces on tonsil and tongue base tissue make tumor identification difficult

5. Anatomy(cont’d)
Sensory and motor innervation is mainly through the glossophayngeal and vagus nerves
otalgia from tympanic and auricular branches
The hypoglossal nerve is motor supply to base of tongue
V2, V3 are motor and sensory supply to soft palate

6. Anatomy Blood supply from external carotid
Lymphatic drainage mainly from levels I, II and III
Tongue base, soft palate, posterior pharyngeal wall drain to both sides
Posterior pharyngeal wall and tonsil drain to retropharyngeal nodes

7. Anatomy(cont’d)
Retropharyngeal space - loose connective tissue between buccopharyngeal fascia and the prevertebral fascia. Extends from skull base to superior mediastinum
Parapharyngeal space - Extends from skull base to hyoid. Contains prestyloid and poststyloid compartments

8. Surgical Considerations
Cure unlikely - extension into poststyloid compartment, prevertebral fascia, or involvement of the carotid artery
Resection of tumor with cm of grossly normal tissue
Frozen sections

9. Four main surgical approaches
Transoral
Transoral/Transcervical
Transpharyngeal
Transmandibular
Choice depends on size and location of tumor and if neck dissection is planned

10. Preoperative assessment
History and Physical
CT, MRI
Neck dissection versus XRT
Selective: Zones I, II and III
MRND or RND

11. Transoral Approach Lip splitting without mandibulotomy Oral
Small(T1), superficial, or exophytic tumors of soft palate, posterior pharynx, ant. tonsillar pillar
Evaluate for trismus, dentition, excess soft tissue, and mandible height.
Initial incision posterior or inferior
Orientation and margins important
Posterior pharyngeal - no skin graft

12. Transoral/Transcervical approach
Lingual-mandibular release
Base of tongue lesions
Incision through floor of mouth from tonsillar pillar to pillar
Tongue and floor of mouth released and pulled below mandible into neck
Risk damage to lingual arteries and nerve and CN 12

13. Transpharyngeal approach
Suprahyoid pharyngotomy
Used for small tumors of base of tongue and posterior pharyngeal walls
Enter into pharynx through the vallecula and extend the incision along the thryoid ala
Downfall is poor visualization of the superior margin of large tumors
Provides excellent functional and cosmetic outcome

14. Pharyngeal Approach(cont’d)
Lateral pharyngotomy
small tumors of base of tongue and pharyngeal walls
enter the pharynx posterior to the thyroid ala on the least diseased side
if more superior exposure need, may extend the pharyngotomy across the vallecula and/or combine with a lateral mandibulotomy

15. Transmandibular Approaches
Mandibulotomy versus mandibulectomy
based on bone invasion
Consider if patient has full set of teeth, limited mouth opening, or posterior location of tumor
Most transmandibular approached require splitting of the lower lip

16. Mandibulotomy
Includes lip splitting approach, midline labiomandibular glossotomy, and mandibular swing approach
Should be made between the two mental foramen and through a tooth socket
Vertical, stair-step, or arrowhead configuration
Select reconstruction plate, adapt, and drill holes prior to mandibulotomy

17. Mandibulotomy (cont’d)
After mandibulotomy, mandible retracted laterally and soft tissue incised
Cuff of 1 cm of floor of mouth mucosa is left on the mandible for closure

18. Lip Splitting Use scalpel to mark vermillion border Vertical
Modified zigzap stepped technique
minimizes vermillion contracture and does not damage facial or mental nerves

19. Midline labiomandibular glossotomy
Rarely used
Useful for small, inferior, midline posterior pharyngeal wall tumors, small midline tongue based tumors, and inferior nasopharyngeal and clival tumors
Lip, gingiva, mandible and anterior tongue are split in the midline. Incision may be carried through the base of tongue

20. Mandibular swing approach
Provides exposure to the entire oropharyx
Procedure of choice for en bloc resection
Useful for tumors that involve multiple sites and/or the parapharyngeal space
Neck dissection first if indicated
Lip splitting and osteotomy next
Full thickness cut in floor of mouth until anterior margin reached

21. Mandibular swing(cont’d)
Mandible and tongue retracted and tumor excised
Posterior exposure improved when mylohyoid m. divided and submandibular gland and its duct are retracted medially
Closure may require a flap and mandible reapproximated and plated

22. Composite resection with mandibulectomy
Consider if mandible is grossly involved with tumor and in cases where mandibular invasion cannot be ruled out.
May need a tracheostomy
Usually need a neck dissection or XRT
Selective, MRND, RND

23. Mandibular resection Marginal Segmental
portion of the mandible(alveolus and medial plate) resected
used when tumor fixed to periosteum
Segmental
condyle to condyle continuity disrupted
used for tumors with gross involvement of the mandible

24. Mandibular resection(cont’d)
Once cancer has accessed the marrow, the surgeon must suspect invasion of the neurovascular bundle
If inferior alveolar nerve sections are positive, the entire canal must be resected
If marrow invasion is suspected, care must be taken to get at least 2 cm margins

25. Composite resection
After neck dissection, the specimen is left attached superiorly at the periostium of the mandible
The massester is then elevated from the angle of the mandible and the periostium incised
Lip splitting or visor flap performed next

26. Composite resection(cont’d)
Cheek flap developed
Anterior mandible cut made with Gigli saw or a reciprocation saw
Posterior mandibular cuts made through the ramus. If ramus involved, the coronoid and condyle are resected.
Mandible is retracted laterally and tumor is excised

27. Visor flap
The visor flap or degloving approach has the following risks: damaging both mental nerves and poor posterior exposure in large tumors
An intraoral incision is made through the buccogingival sulcus to allow elevation of the cheek without a lip split
The incision is usually extended into the contralateral gingivolabial sulcus

28. Reconstruction First, reapproximate the floor of mouth mucosa
Reapproximate and plate the mandible if mandibulotomy
In the case of a mandibulectomy, the mandible is reconstructed with free vascularized bone or a metal reconstruction plate covered with free vascularized or pedicled soft tissue

29. Reconstruction(cont’d)
Close the lip in three layers: orbicularis muscle, mucosa, and skins
Worst complication is nonunion and osteomyelytis

30. Summary
Four main approaches: transoral, transoral/transcervical, transpharyngeal, and mandibular splitting approaches
Preop assessment crucial
History and physical
Bone / Neck involvement
Correct choice of approach ensures adequate tumor resection and saves the surgeon time and frustration