Exam 2: Lecture 18: Principles of Reconstructive surgery Flashcards
Why is reconstructive surgery performed
- to close defects that occur secondary to trauma
- correct or improve congenital abnormalities
- or after removal of neoplasms
what is important to remember about reconstructive surgery
must select the appropriate technique or techniques to prevent complications and avoid unnecessary cost
what do we do to close large or irregular defects
we can use relaxing incisions or “plasty” techniques
what is a pedicle flap
tissues that are partly detached from the donor site and mobilized to cover a defect
what are grafts
involve transfer of a segment of skin to a distant site
what do we try to prevent during surgery
excessive tension, kinking, and/or circulatory compromise
what is hirudiniasis
attachment of a medical leech to the skin
when is hirudiniasis recommended
for tissues with impaired venous circulation
what is a significant risk of hirudiniasis
infection with aeromonas hydrophila
what are the 4 things we should consider when planning reconstructive surgery
- location of wound
- elasticity of surrounding tissue
- regional blood supply
- character of the wound bed (is there infection? is there granulation tissue?)
what happens if you appose incision edges under too much tension
it causes incisional discomfort and pressure necrosis that results in the suture cutting out and partial/complete incisional dehiscence
what are the 5 ways to reduce tension
- undermining wound edges
- selecting appropriate suture patterns
- using relief incisions
- skin stretching
- tissue expansion
T/F: animal is always positioned for surgery such that mobile skin is not pinned against the table or otherwise immobilized
true!! Use pads, flexing appropriate joints, avoiding excessive tension with table ties can accomplish this
how are tension lines formed
by the predominant pull of fibrous tissue within the skin
T/F: General lines of tension are mapped in animals and there are no variations
false! Variations based on breed, conformation, gender, and age
T/F: incisions should be made parallel to tension lines
true
what are the 4 things that are good to know about tension lines (sorry this is a long card)
- traumatic wounds should be closed in direction that prevents/minimizes tension
- wound edges should be manipulated before closure to determine which direction the suture line should run to minimize tension
- if tension is minimal, a wound should be closed in the direction of its long axis
- direction of closure should prevent/minimize created of “dog ears”, or puckers
T/F: parallel skin incision lines require more sutures for closure than perpendicular or oblique
FALSE! Perpendicular/oblique require more sutures for closure
how do you undermine skin adjacent to a wound
by using scissors to separate the skin or panniculus muscle or both from underlying tissues
what is this image showing
undermining skin adjacent to a wound
should we worry about bleeding during undermining
it is usually insignificant but excessive bleeding should be controlled with ligation or electrocoagulation
how do you prevent subdermal plexus injuries
by preserving as much blood supply as you can via an atraumatic surgical technique
what are some ways to use an atraumatic surgical technique
- cut skin with sharp scalpel instead of scissors
- avoid crushing instruments
- manipulate skin with brown-adson thumb forceps, skin hooks, or stay sutures
what things interfere with cutaneous circulation
- wound closure under excessive tension
- rough surgical technique
- division of direct cutaneous arteries
what can happen if we interfere with cutaneous circulation
skin necrosis, wound dehiscence, or infection
how long after a traumatic injury/trauma does a wound/skin declare itself
about 24-48 hours after
why do we use skin stretching and expansion
it is used in reconstructive sx to take advantage of the skins ability to stretch beyond its natural or inherent elasticity
what are the 4 methods for recruiting skin to close wounds under tension
- pre-suturing
- adjustable sutures
- skin stretchers
- skin expanders
when is pre-suturing performed
24 hours prior to sx
when is skin stretchers performed
can be 24-48 hours prior to sx although sometimes you need 96 hours
what are inflatable tissue expanders
inflated in subq tissue to stretch overlying skin
how do inflatable tissue expanders work
they have an inflatable bag and reservoir. you inject a certain pressure or volume at intervals spanning from days to weeks
what type of skin stretching is this
adjustable sutures
T/F: Axial pattern flaps are preferable to tissue expanders for large wound reconstruction
true!!
what are subdermal sutures
sutures that are placed in subdermal or subcuticular tissue to reduce tension on skin sutures and bring skin edges into apposition
what size and type of suture do you use for subdermal sutures
3-0 or 4-0 polydioxanone, poliglecaprone 25, or polyglyconate with a buried knot
what is the purpose of walking sutures
move skin across a defect and obliterate dead space
what are external tension relieving sutures
helps prevents sutures from cutting out which occurs when pressure on skin within the suture loop exceeds the pressure that allows blood flow
what is a standard tension-relieving suture for the skin
vertical mattress suture
what are stents
placing padded material beneath the suture loops
how do we prevent “dog ears”
placing sutures close together on the convex side of the defect and farther apart on the concave side
T/F: dog ear may be incised in the center to form two triangles, one triangle should be excised and the other used to fill the resultant defect
true!
T/F: thick elastic skin is less prone to the formation of dog ears than thin skin
false! Thin elastic skin is less prone
what type of dog ear prevention is this
using unequal suture spacing
what type of dog ear prevention is this
by resecting an elliptic segment of the skin
what type of dog ear prevention is this
by resecting one large triangle of skin
what type of dog ear prevention is this
by resecting two smaller triangles of skin
why do we “relax” incision
allows for skin closure around fibrotic wounds or important structures before radiation therapy or after extensive tumor excision
when should we do relaxing incision
on distal extremities, around the eyes or anus, or to cover tendons, ligaments, nerves, vessels, or implants
how long does it take relief incision to heal
in 25 to 30 days via contraction and epithelialization
what type of closure is this
V-to-Y Plasty
what type of plasty is this
Z-plasty
what things should we do to remove a skin tumor
- skin tension and elasticity should be assessed but excessive tumor manipulation should be avoided
- direction of skin tension lines, shape of excision, and method of closure should be planned before surgery
- a large area should be clipped and aseptically prepped for a change of needing a skin flap for closure
- excision of skin tumors should include the tumor, previous biopsy sites, and wide margins of normal tissue in 3 dimensions (length, width, depth)
what are the margins for removal of a benign tumor
remove the tumor and 1cm of normal tissue
what are the margins to remove malignant tumors
a margin of more than 2-3 cm in all dimensions
what types of tumors should you have greater margins
anything that is aggressive and infiltrative
- mast cells
- melanomas
- Squamous cell carcinoma
- soft tissue sarcoma
- feline mammary adenocarcinomas
- hemangiopericytomas
- infiltrative lipomas
what types of tissues are resistant to neoplastic invasion and are often spared during resection of tumors
cartilage, tendon, ligaments, fascia, other collagen-dense vascular-poor tissues
when should we do a radical tumor excision
when there is poorly localized tumors or those with high-grade malignancy
why do local tumors most often reoccur
because the surgical margins for the original tumor were inadequate
what are the 5 types of skin flaps
- advancement flaps
- rotational flaps
- transposition flaps
- interpolation flaps
- tubed pedical flaps
what is an advancement flap
local subdermal plexus flaps that include single-pedicle, bipedicle, H-plasty, and V-Y advancement flaps
what is a rotational flap
local flap that are pivoted over a defect with which they share a common border
what is a transposition flap
rectangular, local flaps that bring additional skin when rotated into defects
what type of flap is this
transpositional flap
what category of flap is this (not V-Y)
advancement flap
what type of flap is this
rotational flap
what is a interpolation flap
a variation of the transposition flap, leaves an area of interposed skin between the donor bed and recipient wound
what is a tubed pedical flap
a tubed pedicle flap uses a multistaged procedure to “walk” an indirect, distant flap to recipient site
what type of flap is this
tubed pedical flap
what is an axial pattern flap
it includes a direct cutaneous artery and vein at the base of the flap. It has better perfusion than pedicle flaps with a circulation from the subdermal plexus alone
what are the 9 direct cutaneous vessels used in axial pattern flaps
- caudal auricular
- omocervical
- thoracodorsal
- caudal superficial epigastric
- medial genicular
- deep circumflex iliac
- superficial lateral caudal
- superficial brachial
- superficial temporal
what are the different type of skin grafts
full thickness grafts, sheet grafts, plug/punch/seed and strip grafts, mesh grafts, and split thickness skin grafts
