145d coclia99 grafts and flaps
TRANSCRIPT
COCLIA 99:Grafts and Flaps in
Head & Neck Surgery
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Skin Overview
• Epidermis– stratified squamous
epithelium– no blood vessels:
receives nutrients by diffusion
Skin Overview
• Dermis– 2 layers: papillary &
reticular– reticular dermis: larger
blood vessels, epidermal appendages
– intradermal epithelial structures (sebaceous & sweat glands, hair follicles) are lined with epithelial cells with the potential for division and differentiation
STSG vs. FTSG
• STSG– Entire epidermis and a dermal component of variable thickness
• thin (0.005-0.012 inches)• intermediate (0.012-0.018 inches)• thick (0.018-0.030 inches)
– Thicker STSG requires more favorable conditions because of the greater amount of tissue requiring revascularization
– Much broader range of application than FTSG
• FTSG– Entire epidermis and dermis– Retains more characteristics of normal skin (color, texture, thickness) – Undergoes less contraction while healing– Limited to relatively small, uncontaminated, well-vascularized wounds
• Describe the three stages of survival for a STSG…
The Three Stages
• 3 stages– Imbibition (“to drink”): absorbs nutrients from
underlying recipient bed; initial 2-3 days– Inosculation (“to kiss”): blood vessels in the skin
graft grow to meet the blood vessels in the recipient bed; days 4-6
– Neovascularization: new blood vessels form bridging the graft to the recipient bed; days 6-7
• What factors are important in graft survival?
Survival Factors
• Good– Nutrition and oxygenation delivery– Removal of waste products
• Bad– Mobility of graft– Infection – Fluid collection beneath graft
• How are STSG and FTSG harvested?
STSG Harvesting
• Dermatome– Uniform thickness (set width and
thickness)
– Fast
– Must be familiar with equipment
– 15 blade scalpel simulates 0.015 inches
• Free hand with scalpel– Variable thickness
– Irregular edges
FTSG Harvesting
• Free hand with scalpel
• Enlarge by 3-5%– Compensates for immediate primary contraction
• MUST trim off all residual adipose tissue– Relatively avascular
• What is the point of meshing?
STSG Meshing
• Allows expansion up to 9 times the donor site
• Purposes– Cover large surface area– Recipient site is irregularly
contoured
• The larger the size mesh the more fragile the graft
• How is “pie-crusting” different from meshing?
Pie-Crusting
• Multiple stab wounds through the graft– Made with scalpel or scissors
• Allows egress of wound fluid
• Does not expand surface area
• How can you manage the donor graft site (STSG and FTSG)?
STSG Donor Site
• Options– Semi-occlusive dressings (Op-Site, Tegaderm)
• Shown to be superior: transparent, sterile, moist
– Semi-open dressings (Vaseline gauze, Xeroform)• Might damage new fragile epithelial layer when
removed
– No dressing
• Healing – begins within 24 hours of harvesting– directly proportional to the number of epithelial appendages– inversely proportional to the thickness of graft
FTSG Donor Site
• Usually closed primarily
• Can cover with STSG (rarely done)
Flap Classification
• by arrangement of their blood supply– random, arterial
• by the method of transfer– advancement, pivotal, hinged
• by configuration– rhomboid, bilobed
• by location – local, regional, distant
• What is the difference between random and axial pattern flaps?
• Give examples of each type
Random Pattern Flaps
• Do not have named arterial or venous vessels
• Rely on blood flow through dermal and subdermal plexus
• Eventually connects with perforating vessels (neovascularization)
• Limited in length and width
Random Pattern Flaps
• Advancement flap
• Rotation advancement flap
• Rhomboid flap
Axial Pattern Flaps
• Rely on blood supply from named direct cutaneous arteries and veins – Runs along longitudinal flap axis – Runs in subcutaneous tissue superficial to muscle
• Flap blood supply secure for at least length of blood vessels
• Can further lengthen flap with tacking on random pattern flap at distal end
Axial Pattern Flaps
• Nasolabial flap – angular
• Median or paramedian forehead flaps– supratrochlear
• Lateral forehead flap– superficial temporal
• What is a Burow’s triangle?
Burow’s Triangle
• A triangle of skin can be excised from the base of a flap to aid in closure
• Effective for correcting dog ears
Flap Classification
• by arrangement of their blood supply– random, arterial
• by the method of transfer– advancement, pivotal, hinged
• by configuration– rhomboid, bilobed
• by location – local, regional, distant
• Discuss these flaps:– advancement– transposition – rotation– interpolation
Advancement Flap
• The flap’s leading edge moves into the defect
• Flap movement is longitudinal rather than rotational
• Burow’s triangles can be excised from the base of the flap to aid in closure
Transposition Flap
• Movement of adjacent skin from an area of excess to the area of deficiency
• Moves laterally about a pivot point into an adjacent defect
• Usually rectangular configuration
• Donor site can be closed primarily
• Examples: rhomboid flap, Z-plasty
Rotation Flap
• Moves adjacent tissue rotated in an arc around a pivot point
• Relies on perforators that course superficially to supply the dermal and subdermal plexuses
• Length of the flap's perimeter should be at least 4 times the width of the defect
Interpolation Flaps
• Rotates about a pivot point into a nearby but not adjacent defect
• Usually linear configuration• Pedicle passes above or
below a skin bridge• Base is located at some
distance from the defect• Flap is subsequently
detached in a second surgical procedure
Flap Classification
• by arrangement of their blood supply– random, arterial
• by the method of transfer– advancement, pivotal, hinged
• by configuration– rhomboid, bilobed
• by location – local, regional, distant
Rhomboid Flap
• Pedicle width controls the amount of circulation within the dermal-subdermal plexus
• Closed with a choice of 4 different flaps
• Line of tension is greatest at donor site
• Point of greatest tension is at “C”
Rhomboid Flap
Bilobed Flap
• Each lobe of the flap is tethered to a cutaneous pedicle
• Two important variables: flap length, flap angle
• 1st lobe is designed to be equal to the width of the original defect
• 2nd lobe is constructed with an elliptical tip to facilitate side-to-side closure of the tertiary defect
• What is the safe length-to-width ratio of a flap?
Length-to-Width Ratio
• 3:1 used as a rough guideline only• Face is very vascular• Random pattern pedicled flap blood supply originates
from nearest cutaneous arterial perforator at the base• Surviving length: determined by the perfusion
pressure of the feeding vessels and the intravascular resistance
• Increasing the width of a flap’s base does not increase the survivng length of the flap
Flap Classification
• by arrangement of their blood supply– random, arterial
• by the method of transfer– advancement, pivotal, hinged
• by configuration– rhomboid, bilobed
• by location – local, regional, distant
• Describe some common regional flaps used in head and neck reconstruction
• Give the blood supply for each
Common Regional Flaps
• Pectoralis major
• Deltopectoral
• Latissimus dorsi
Pectoralis Major
• Myocutaneous flap• Pectoral branch of the
thoracoacromial artery • Advantages: bulk,
reliability, one-stage procedure
• Disadvantages: bulk, insensate, tend to tether adjacent mobile structures
• Can reach as high as the nasopharynx
Deltopectoral
• Faciocutaneous flap
• Perforating branches of mainly the first four intercostal arteries
• Skin graft is needed to reconstruct part of the donor site
Latissimus Dorsi
• Thoracodorsal artery
• Useful to line large defects (sizable, bulk)
• Disadvantage: potential for kinking of the feeding vessels at the shoulder
Nasolabial Fold Reconstruction
• Maintain nasolabial crease
• Do not distort lip or nasal alae
• Rhomboid flap
• Bilobed flap
• Advancement flap
Nasolabial Flap
• Medial cheek tissue located lateral to the nasolabial crease
• Random blood supply from branches of the facial artery
• Based either superiorly or inferiorly
• Superiorly based: lower two thirds of the nose (nasal dorsum, alae, tip)
• Inferiorly based: upper lip, floor of nose, columella
Medial Canthus Reconstruction
• Rhomboid flap
• Bilobed flap
• Modified glabellar flap
• Eyelid myocutaneous flap
Indian Forehead Flap
• Midline forehead flap
• Blood supply: paired supratrochlear vessels
• Incision: hairline to nasofrontal angle, penetrated to periosteum
• 3 weeks: pedicle divided