Head and Neck


Navid Jallali & Hyder Ridha

Introduction
The head and neck is a complex anatomical region:
  • it is a visible area that partly defines a person
  • it contains specialised structures that may be ‘static’ and/or ‘dynamic’ in function
The reconstructive surgeon must consider such factors to provide the optimal functional and cosmetic outcome. Free tissue reconstruction in the head and neck is commonly required following:
  • cancer ablative surgery
  • trauma
  • loss of facial nerve function
Aerodigestive areas
The upper aerodigestive tract is divided into six areas. Reconstruction with a free flap is most commonly required in the oral cavity as tumours at this site are less responsive to chemoradiotherapy and are accessible. Whilst pedicled flaps, such as the pectoralis major flap, may be used in the head and neck we prefer free tissue transfer:
it allows replacement of ‘like with like’ tissue that is mobile and can allow unrestricted movement it brings healthy, well vascularised tissue to regions that may have received or will receive radiotherapy as part of treatment

Recipient vessels
The head and neck is rich in potential recipient vessels. It is important that vessels are chosen carefully, taking into consideration:
  • site of reconstruction
  • pedicle length
  • vessel calibre
Arteries for reconstruction

Recipient Artery
Intraoral defects and the lower 1/3 of the face:
Facial artery:
  • common primary option
  • easily accessible; it is identified during neck dissections and is close to these defects
  • calibre 2.0 - 3.0 mm
  • suitable for end-to-end anastomosis
Superior thyroid artery:
  • a second choice
  • also identified during neck dissections
  • calibre 1.5 - 2.0 mm - good flow but is often smaller than the facial artery
  • situated lower down the neck below the level of the hyoid and, therefore, a longer pedicle is required.
For scalp and upper 2/3 of the face, maxilla/midface :
  • Superficial temporal artery and vein:
    • ideal position in the midface
    • calibre 1.5 - 2.5 mm
    • a separate incision is required to prepare the vessels for microanastomosis
Recipient Vein
Veins for reconstruction 

For lower 1/3 of the face
  • facial vein with end-to-end anastomosis
  • internal jugular vein with end-to-side anastomosis
Vessel Access
Patients undergoing free tissue transfer often have some form of neck dissection as part of their resection surgery, thereby identifying potential recipient vessels. Patients with mucosal SCC (squamous cell carcinoma) with node negative necks undergo a selective neck dissection, whereas those with nodal disease undergo a modified radical neck dissection.

In situations where a neck dissection is not indicated, such as benign disease (ameloblastoma) or certain types of salivary gland tumours, then vessels must be dissected and prepared for anastomosis. One option is to use the superficial temporal vessels; the temporal artery is palpated and an incision is made adjacent to the vessel communicating with the defect. This avoids neck surgery. The other option is to perform an ‘access neck dissection’; this involves removal of level Ib (the submandibular gland), exposing the facial artery and the common facial vein.

Flap Options
Commonly used reconstructions for oral cavity defects:
  • mucosa only:
    • tongue - less than half - radial forearm
      Radial forearm flap

    • tongue - hemi-tongue - ALT (anterolateral thigh flap) or lateral arm
      ALT Flap




    Lateral arm flap
    • tongue - more than half - ALT +/- vastus lateralis
    • floor of mouth - radial forearm or lateral arm
    • retromolar trigone - radial forearm or ALT
  • mucosa and bone:
    • mandible - fibula fasciocutaneous or fibula + radial forearm
    • hard palate - scapula tip or DCIA or ALT
      DCIA flap
  • pharyngolaryngectomy
    • partial - RF or pedicled pec major
    • circumferential - jejunum or tubed ALT
Vessel Anastomosis
In general, the arterial anastomosis is carried out end-to-end. The venous anastomosis is usually end-to-side if anastomosing to the IJV and end-to-end if anastomosing to the common facial vein.
The challenges of head and neck microsurgery include vessel mismatch, severely atherosclerotic recipient vessels and vessel fibrosis from previous chemoradiotherapy treatment. Meticulous technique is paramount in order to compensate for vessel size and wall thickness discrepancies, to prevent plaque fracture and to avoid intimal separation. Manoeuvres such as spatulating or bevelling vessel ends may be useful.

Common Problems

Increasingly patients presenting are requiring free tissue transfer having previously had chemoradiotherapy as their primary treatment or with a second head and neck cancer. Such patients present a challenge as the often have vessel-depleted necks from their previous treatment. In such cases, alternative vessels must be considered:
  • transverse cervical vessels - level V
  • contralateral neck vessels
  • out-of-region vessels - internal mammary vessels or cephalic vein - 'cephalic turn up'
Vein grafts are often needed to increase pedicle length.
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