Surgical Approaches to the Oropharynx - PowerPoint

							Surgical Approaches to the
       Oropharynx


     Karen Stierman, M.D.
   Christopher Rassekh, M.D.
        January 13, 1999
                 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
           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
           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
           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
                 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
           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
      Surgical Considerations
• Cure unlikely - extension into poststyloid
  compartment, prevertebral fascia, or
  involvement of the carotid artery
• Resection of tumor with 1 - 2 cm of grossly
  normal tissue
• Frozen sections
    Four main surgical approaches
•   Transoral
•   Transoral/Transcervical
•   Transpharyngeal
•   Transmandibular
•   Choice depends on size and location of
    tumor and if neck dissection is planned
      Preoperative assessment
• History and Physical
• CT, MRI
• Neck dissection versus XRT
  – Selective: Zones I, II and III
  – MRND or RND
         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
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
    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
  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
  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
            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
      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
               Lip Splitting
• Use scalpel to mark vermillion border
• Vertical
• Modified zigzap stepped technique
  – minimizes vermillion contracture and does not
    damage facial or mental nerves
      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
    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
     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
     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
        Mandibular resection
• Marginal
  – 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
   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
         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
   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
                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
            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
       Reconstruction(cont’d)
• Close the lip in three layers: orbicularis
  muscle, mucosa, and skins
• Worst complication is nonunion and
  osteomyelytis
                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