ENT SC021: Head And Neck Cancer Problems: Function And Shape Flashcards
Sub-regions in head and neck area
- Skull base
- Salivary glands (major: parotid, submandibular, sublingual; minor: distributed throughout oral cavity and paranasal sinuses)
- Paranasal sinuses
- Nasal cavity
- Nasopharynx (above soft palate)
- Oral cavity
- Oropharynx (soft palate to epiglottis)
- Hypopharynx (below hyoid / epiglottis)
- Larynx (communication between airway and digestive tract)
- Trachea
Surgery in NPC
Surgery: only for recurrence, primary treatment: RT +/- Chemo
H+N cancer problems
- Large number of important + vital organs concentrated in a small area
- H+N: most frequently exposed region of the body —> anatomical disruption —> affect **Morphology + **Physiology
- Disfigurement of external appearance
- ∵ systemic metastasis are uncommon —> reasonable life-expectancy - Breathing
- Mastication / Swallowing
- Pain
- Bleeding
- Smelly
***Major functions and problems of H+N area
- Vision
- Visual acuity: Unilateral / Bilateral
- Dry eye: Post-irradiation for NPC
- Epiphora: Lacrimal duct drainage system (can be damaged by RT / surgery)
- Diplopia: EOM / Periorbita (e.g. tumour compressing on EOM)
- Dystopia: Lost of orbital floor (e.g. inferior displacement of globe) - Airway
- Temporary: Swelling (e.g. post-surgery —> require prophylatic tracheostomy)
- Permanent: Tumour / Stricture (may require tracheal resection or even laryngectomy) - Taste
- Temporary: Post-chemotherapy
- Permanent: Post-irradiation / Surgery (∵ salivary glands are affected / destroyed) - Swallowing
- ***Voluntary phase: usually affected by tumours in H+N region
—> usually immediately after glossectomy / pharyngectomy
—> sometimes delayed presentation after RT
—> need to assess pre + post-surgery - Speech
- Phonation: post-laryngectomy
- Articulation: post-glossectomy / nasal / paranasal sinus surgery
Aim of Surgery in H+N cancers
2 components:
1. Resection
- Oncologically clear yet preserve important organ functions
—> Margin of resection
- Reconstruction (functional + cosmetic)
- Choose the best option for individual patient (restore / replace)
Margins of resection
Cater for submucosal spread / satellite lesions / microscopic spread
- Facial basal cell carcinoma: 3-5 mm
- Squamous cell: 5-15 mm
- Melanoma: 5-30 mm
- Dermatofibrosarcoma protuberans: 30-50 mm
***Tools for reconstruction
“Ladder of reconstruction”
- From simple to difficult
—> Direct closure (simply approximate wound edges, simplest) —> Skin graft —> Local flap —> Distant flap —> Free Flap (most complex)
- Does not take into account the aesthetic and functional results of reconstruction
- Direct closure:
Advantages:
- Simple
Disadvantages:
- But after direct closure the morphology of remnant may be ***deformed
2. Skin graft: Advantages: - Simple - Thin and pliable - Minimal donor site morbidity - Can be used as a mean of dressing temporarily until underlying tissue heal back together
Disadvantages:
- ***Need a well-vascularised bed
- ***Poor tolerance to infection (e.g. oral cavity is a contaminated site —> skin graft is prone to infection)
- ***Secondary contracture
- Local flaps (e.g. Nasolabial flap, Transposition flap, Bilobed flap, Rhomboid flap, Mustarde cheek flap)
Advantages:
- **Simple
- Tissue used is identical to tissue removed —> good colour, texture, consistency match
- **Minimal donor site morbidity
Disadvantages:
- ***Difficult to design (e.g. arch of rotation)
- Partial / Complete necrosis
- Microvascular free flaps
Advantages:
- Particular flap for particular defect
Disadvantages:
- ***Longer operative time (need magnifying glass for microvascular anastomoses)
- ***Expertise
- Risk of ***flap necrosis (if poor anatomoses)
Tissue expansion
Expand normal surrounding skin (撐鬆皮膚) —> Excess skin formed —> can now approximate loose skin after surgery
***Graft vs Flap
Graft:
- Need to develop its own blood supply from the recipient bed
- Reliant on clean bed, no infection / bleeding, no shearing force
Flap:
- **Local (Tissue around defect) / **Regional (Tissue away from defect, e.g. pectoralis major myocutaneous flap (based on thoracoacromial vessels), deltopectoral flap (based on internal mammary arteries), latissimus dorsi flap (based on thoracodorsal vessels)) / **Distant / **Free
- Need to bring along its own blood supply from its blood vessels
Microvascular free flaps
- No pedicle (vs other local / regional / distant flaps)
- Tissues from totally unrelated body parts (i.e. can use tissues from lower body)
- Flap totally disconnected from its blood supply —> transfer to H+N area —> reconstitute blood supply by microvascular anastomoses
- More freedom in design / choice of reconstruction (e.g. can use skin only (less bulk) / together with muscle vs local / regional / distant flaps: entire muscle need to be transferred with skin to preserve blood supply to skin)
Examples:
- Anterolateral thigh flap (based on lateral circumflex femoral vessels)
- Vertical rectus abdominis myocutaneous flap (based on deep inferior epigastric vessels)
- Free jejunum flap (for pharygneal / esophageal / tubular mucosal defect, based on jejunal vessels)
- Free fibula flap (can be used as bone flap / osteocutaneous flap, based on peroneal vessels)
- Free radial forearm flap (based on radial artery, cephalic vein)
- Posterior tibial flap (based on posterior tibial artery)
Choice of flaps
Depend on:
- ***Site
- ***Size
- ***Length of pedicle
- ***Type and quality of blood vessels
Vision in H+N surgery
Protection of the functioning eye during anaesthesia:
- Eye shield
- Chloramphenicol ointment
- Tarsorrhaphy (suture upper and lower tarsal plate —> keep eye shut)
- Knowing the anatomy
***Temporary vs Permanent tracheostomy
Temporary:
- Only cut a slit in anterior wall of trachea, posterior wall not touch —> still continuous with nose
Permanent:
- Trachea brought to overlying skin circumferentially —> Patient breathe through tracheostome rather than nose
Swallowing
- Oral cavity
- Anterolateral thigh flap - Oropharynx
- Pectoralis major myocutaneous flap - Hypopharynx
- Free jejunal flap
Speech
- Esophageal speech (more natural but cannot speak for long sentences, no need for device, harder to produce voice if full stomach)
- Pneumatic device (not hygienic method)
- Electronic device (sound very monotonic)
- Speaking valves
- one way valve (installed in Tracheoesophageal fistula): air go from trachea into esophagus but food cannot go into trachea
