Principles of Reconstructive Surgery (18) Flashcards
Dr. Thompson
Why is reconstructive surgery commonly performed?
- close defects that occur secondary to trauma
- correct or improve congenital abnormalities
- after removal of neoplasms
Large or irregular defects can be closed sometimes using _____
- relaxing incisions or “plasty” techniques
- pedicle flaps
- grafts
Large defects or those on the extremities may require that tissue be mobilized from other sites:
pedicle flaps
grafts
What are pedicle flaps?
tissues that are partly detached from the donor site and mobilized to cover a defect
What are grafts?
involve the transfer of a segment of skin to a distant (recipient) site
What is hirundiniasis?
attachments of leeches to the skin
When is hirundiniasis used?
recommended only for tissues with impaired venous circulation
leeches produce a small bleeding wound that mimics venous outflow
What happens when the apposing incision edges are under too much tension?
causes incisional discomfort and pressure necrosis, resulting in sutures “cutting out” and partial or complete incisional dehiscence
What are methods of reducing tension?
- undermine wound edges
- selecting appropriate suture patterns
- using relief incisions
- skin stretching
- tissue expansion
How do you position an animal for surgery to minimize tension?
mobile skin not pinned against the table or otherwise immobilized - using pads, appropriate joint flexion, table ties
How are tension lines formed?
by the predominant pull of fibrous tissue within the skin
varies
How should incisions be made regarding tension lines?
should be made parallel to tension lines
What happens if you do not incise the skin parallel to the tension lines?
- less healing
- gaping
- curvilinear shape
- more sutures for closure
- more likely to dehisce
What is good to know about tension lines?
What are the tension lines in dogs?
What is the simplest tension-relieving procedure?
undermining skin adjacent to a wound
What are the characteristics to undermining skin adjacent to the wound?
- skin/panniculus muscle separated from underlying tissue using scissors
- full elastic potential can be used
- deep to the panniculus muscle layer to preserve subdermal plexus and direct cutaneous vessels
Before wound closure, what should you do?
use scissors to undermine skin and subcutaneous tissue or skin and panniculus and to separate them from the underlying tissue
metzenbaum scissors
T/F: Bleeding is usually insignificant during undermining
TRUE
How do you prevent subdermal plexus injury?
use atraumatic surgical technique
- sharp scalpel blade instead of scissors
- avoid crushing instruments
- brown-adson, skin hooks, stay sutures
What interferes with cutaneous circulation?
- wound closure under excessive tension
- rough surgical technique
- division of direct cutaneous arteries
How do you deal with skin stretching and expansion?
can be prestretched - pressuring, adjustable sutures, skin stretchers, and skin expanders
What are the 4 things you can do to recruit skin to close wounds under tension?
- presuturing
- adjustable sutures
- skin stretchers
- skin expanders
What does this picture depict?
presuturing - performed 24 hours before surgery
What are skin stretchers?
noninvasive device capable of stretching skin both adjacent to and distant from the surgical site
Technique?
skin stretchers
What is this?
inflatable tissue expanders
What are the characteristics of inflatable tissue expanders?
- inflated in subcutaneous tissue to stretch overlying skin
stretched every 2 to 7 days, takes days to weeks
Technique?
adjustable sutures
What is preferable to tissue expanders for large wound reconstruction?
axial pattern flaps
What are subdermal sutures?
reduce tension on skin sutures and bring skin edges into apposition
3-0 or 4-0 PDS, etc with a buried knot
What are the purposes of walking sutures?
- move skin across a defect
- obliterate dead space
- distribute tension over the wound surface
How do you place a walking suture?
skin is advanced toward the center of the wound by placing rows of interrupted, subdermal sutures beginning at the depths of the wound
How should walking sutures be placed?
place the suture through the fascia of the body wall at a distance closer to the center of the wound than the bite through the subdermal fascia or deep dermis
What is the purpose of external tension relieving sutures?
help prevent sutures from cutting out, which occurs when pressure on skin within the suture loop exceeds the pressure that allows blood flow
reduces pressure by spreading it over a larger area of skin
The standard tension-relieving suture for the skin is the ______
vertical mattress suture
What is stenting?
placing padded material beneath the suture loops
How do you prevent dog ears?
- placing sutures close together on the convex side of the defect and farther apart on the concave side
- outlining with an elliptic incision, removing redundant skin, and apposing the skin edges in a linear or curvilinear fashion
- incised in the center to form two triangles; one triangle excised and the other used to fill the resultant defect
- both triangles may be excised and the edges apposed, creating a linear suture line
[Thick/Thin] elastic skin is less prone to the formation of dog ears
Thick - many dog ears flatten without excision
What is this technique showing prevention of dog ears?
put suture in the middle - closer on one side and wider on another side
use unequal suture spacing
What is this technique showing prevention of dog ears?
resecting an elliptic segment of skin
What is this technique showing prevention of dog ears?
resecting one large triangle of skin
- creates dog ear at end - split down dog ear and go to bottom piece and cut bottom triangle off with No. 15 blade
What is this technique showing prevention of dog ears?
resecting two smaller triangles of skin
prevents puckers and dog ears
What are relaxing incisions?
allows skin closure around fibrotic wounds or over important structures
- before radiation therapy
- after extensive tumor excision
When are relaxing incisions indicated?
- on distal extremities
- around the eyes and anus
- cover tendons, ligaments, nerves, vessels, or implants
When do simple relaxing incisions heal?
relief incisions by contraction and epithelialization in 25 to 30 days
- some surrounded by loose elastic tissue can be closed primarily after the wound is approximated
What are multiple punctate relaxing incisions?
What does this depict?
made a relaxing incision near the defect to allow skin apposition
What does this image depict?
multiple punctate relaxing incisions
What is a V-to-Y plasty?
provides an advancement flap to cover the wound
What does this depict?
V-to-Y plasty
close it from each side till it meets in the middle
then, close at the bottom
When is a Z-plasty used?
can be made adjacent to or involving the wound to allow wound closure
What does this image depict?
Z to S plasty
What do you need to remember for a Z to S plasty?
- parallel to the greatest lines of tension (perpendicular to the incision you are closing)
- 1/3rd to 1/2 the length of the incision you are closing
- 60 degree angle on “limbs of the Z”
Where do you place the Z plasty?
usually > 3cm from the primary incision
When should you undermine the tissue in a Z-plasty?
- the Z-plasty
- both sides of the primary incision you are closing
- the skin in between the two incision
How do you remove skin tumors?
What are the margins of benign tumors?
remove the tumor and 1 cm of normal tissue
What are the margins of malignant tumors?
a margin of more than 2 to 3 cm may be necessary for complete local excision
- margins are taken in all dimensions, including the deep margin if feasible
How are aggressive, infiltrative tumors removed?
margin distance should be greater
What are resistant to neoplastic resection?
cartilage, tendon, ligaments, fascia, other collagen-dense, vascular-poor tissues
Excision of infiltrative or aggressive tumors should extend at least _______ below the detectable tumor margins
one fascial layer
How do you remove poorly localized tumors or those with high-grade malignancy?
radical tumor excision (i.e. removal of an entire compartment or structure, amputation, or lobectomy)
What is super important to know about excision of infiltrative or aggressive tumors?
should included greater than 2 to 3 cm of “normal” tissue around the lesion
extend the dissection at least one fascial layer below the detectable tumor margins
Why do most local tumors recur?
because the surgical margins for the original tumor were inadequate - mark tumor borders
What does this show?
a surgical marker was used to delineate a 2 to 3 cm margin for excision of a malignant tumor involving the skin and subcutaneous tissues
What are the types of skin flaps for wound closure?
- advancement flaps
- rotational flaps
- transposition flaps
- interpolation flaps
- tubed pedical flaps
What are advancement flaps?
local subdermal plexus flaps
flaps are formed in adjacent, loose, elastic skin that can be slid over the defect
What is this called?
V-to-Y plasty
What kind of flap?
advancement flap
What are rotational flaps?
local flaps that are pivoted over a defect with which they share a common border
What are transposition flaps?
rectangular, local flaps that bring additional skin when rotated into defects
90 degree transposition flaps are aligned parallel to the lines of greatest tension to obtain the bulk of the flap required to cover the defect
What are characteristics of transposition flaps?
- the width of the flap = the width of the defect
- length of flap: determined by measuring from the pivot point of the flap to the most distant point of the defect
What flap is this?
transposition flaps
What are interpolation flaps?
a variation of the transposition
lacks a common border with the wound
What are tubed pedical flaps?
uses a multistage procedure to “walk” an indirect, distant flap to a recipient site
What are axial pattern flaps?
include a direct cutaneous artery and vein at the base of the flap
have better perfusion than pedicle flaps with a circulation from the subdermal plexus alone
What is a caudal superficial epigastric flap?
What are skin grafts?
may be meshed by making small, full-thickness incisions through the graft
incisions are aligned in parallel rows
