Lecture 18: Principles of Reconstructive Surgery (Exam 2) Flashcards
When is reconstructive surgery performed
- Close defects that occur secondary to trauma
- Correct or improve congenital abnorms
- After removal of neoplasms
What is important in reconstructive surgery
To select the appropriate technique or techniques to prevent complications & avoid unnecessary cost
How are large or irregular defects sometimes closed
Relaxing incision or “plasty” techniques
Define pedicle flaps
Tissues that are partly detached from the donor site & mobilized to cover a defect
Define a graft
The transfer of a segment of skin to a distant (recipient) site
Why is it important to have careful planning & meticulous atramautic surgical tech
To prevent excessive tension, kinking, & circulatory compromise
What reconstructive tech can survive on avascular bed
Properly developed & transferred local flaps
Which reconstructive tech requires vascular bed
Grafts & distant flap transfers
Describe Hirudiniasis
- Attachment of leeches to the skin
- Only for tissues impaired w/ venous circulation
- The leech eats an avg of 5 ml of blood but blood oozes from the wound for 24 to 48 H after the leech detaches b/c of anticoagulants & vasodilator substances introed into the wound
What should be considered when planning reconstructive surgery
- Location of the wound
- Elasticity of surrounding tissue
- Regional blood supply
- Character of the wound be
What happens when apposing incision edges are under too much tension
- Incisional discomfort
- Pressure necrosis
- Sutures “cutting out”
- Partial or complete incisional dehiscence
What are methods of reducing tension
- Undermining wound eges
- Selecting appropriate suture patterns
- Using relief incisions
- Skin stretching
- Tissue expansion
How is an animal positioned in surgery
Mobile skin is not pinned against the table or otherwise immobilized
If these methods do not allow primary appositon what can happen
- The wounds may be allowed to heal by secondary intention
- May be reconstructed w/ flaps or grafts
How do tension lines form
By the predominant pull of fibrous tissue w/in the skin
Where should incisions be made
Parallel to tension lines to be able to heal better & not gapes
What is good to know about tension lines
- Traumatic wounds should be closed in the direction that prevents or min tension
- Wound edges should be manipulated before closure to determine which direction the suture line should run to min tension
- If tension is min a wound should be closed in the direction of its long axis
- The direction of closure should prevent or min the creation of “dog ears” or puckers @ the ends of suture line
What incisions require more sutures
Perpendicular (A) & oblique (B) gape & req more sutures for closure than incisions that are parallel to skin tension lines
Why should wound edges be manipulated
To determine the direction of least tension & minimal “dog ear” formation
Describe undermining skin adjacent to the wound to relieve tension
- Skin is undermined by using scissors to separate the skin or panniculus muscle (or both) from underlying tissue
- Simplest tension-relieving proceudre
- Releases skin from underlying attachments so that its full elastic potential can be used
- Skin should be undermined deep to the panniculus muscle layer to preserve subdermal plexus & direct cutaneous vessels that run parrallel to the skin surface
How can bleeding be stopped during undermining of tissue
- Electrocoagulation
- Ligation
- Skin tension & bandaging usually controls hemorrhage & prevents seromas
How is a subdermal plexus injury prevented
- Cut skin w/ a sharp scalpel blade instead of scissors
- Avoid crushing instruments
- Manipulate skin w/ brown-adson thumb forceps, skin hooks, or stay sutures
What interfere w/ cutaneous circulation
- Wound closure under excessive tension
- Rough surgical tech
- Division of direct cutaneous arteris
What can happen if cutaneous circulation is not preserved
- Skin necrosis
- Wound dehiscence
- Infection
Describe skin stretching & expansion
Tech used in reconstructive surgery that takes advantage of the skin’s ability to stretch beyond its natural or inherent elasticity
When can skin be prestretched & why
- Hours to days before surgery
- Allow closure w/ less tension @ the time of the procedure
What are some methods for recruiting skin to close wounds under tension
- Presuturing
- Adjustable sutures
- Skin stretchers
- Skin expanders
Describe skin stretchers
- Noninvasive device capable of stretching the skin both adjacent to & distant from the surgical site
- More skin can be stretched or recruited in this tech
Describe inflatable tissue expanders
- Inflated in SubQ tissue to stretch overlying skin
- Expanders have an inflatable bag & reservoir
- Gradual expansion involves injecting to a given pressure or volume @ intervals spanning days to weeks (every 2 to 7 days)
- When the tissue is sufficiently stretched to allow reconstruction the device is removed & a skin flap is created to close the defect
What is this
Adjustable sutures
What flaps are preferable to tissue expanders for large wound reconstruction
Axial pattern flaps
Describe subdermal sutures
- Sutures place in subdermal or subcuticular tissue to reduce tension on the skin sutures & brine skin edges into apposition
- Reduce scarring
What fascia is strong & tolerates tension better than SubQ tissue or skin
Subdermal fascia
What suture is used for subdermal & subcuticular sutures
- 3-0 or 4-0 polydioxanone
- Poliglecaprone 25
- polyglyconate suture w/ a buried know
Describe walking sutures
- Move skin across a defect
- Obliterate dead space
- Distribute tension over the wound surface
- Skin is advanced toward the center of the wound by interrupted subdermal sutures @ the depths of the wound
- Sutures placed through fascia of the body wall closer to the center of the wound than the bite through the subdermal fascia or or deep dermis
What are the steps of placing walking sutures & advancing the skin toward the center of the wound
- Place the suture through the fascia of the body wall @ a distance closer to the center of the wound than the bite through the subdermal fascia or deep dermis
- The distance from A to B increases b/c of the skin stretching when the suture is tied
Describe external tension relieving sutures
- Helps prevent sutures from cutting it which occurs when pressure on the skin w/in the suture loop exceeds the pressure that allows blood flow
- Pressure is reduced by spreading it over a larger area of skin
- Placing sutures farther from the skin edge or using mattress or cruciate sutures helps disperse pressure
Describe a standard tension relieving suture for the skin
- The vertical mattress suture
- Placed 1 to cm away from the primary row of sutures apposing the skin edges
- Are placed while the skin is approx w/ towel clamps/ skin hooks
- Can be removed by the third day after surgery
Describe stents
Placing padded material beneath the suture loops
What are some other suture patterns that relieve tension
- Alternating wide & narrow bites using simple interrupted sutures
- Placing pulley sutures
- Horizontal mattress sutures w/ or w/out rubber tubing stents
How is “dog ears” prevented
- Placing sutures close together on the convex side of the defect & farther apart on the concave side
- Outlining w/ an elliptic incision removing redundant skin & apposing the skin edges in a linear or curvilinear fashion
How can “dog ears” be corrected
- May be incised in the center to form two triangles; one triangle should be excised & the other used to fill the resultant defect
- Both triangles may be excised & the edges apposed creating a linear suture line
T/F: Many dog ears flatten w/out excision
True
What skin is less prone to the formations of dog ears
Thin elastic skin is less prone than thick skin
What do relaxing incisions allow for
Skin closure around fibrotic wounds or impt structures before radiation therapy or after extensive tumor excision
Where are relaxing incisions indicated
- On distal extremities
- Around the eyes & anus
- To cover tendons, ligaments, nerves, vessels, or implants
When do relief incisions heal
- By contraction & epithelialization in 25 to 30 days
- Some that are surrounded by loose elastic tissue can be closed primarily after the wound is approximated
Describe using multiple punctate relaxing incisions
- Small, parallel, staggered incisions made in skin adjacent to a wound to allow closure w/ reduced tension
- Are more cosmetic than single relaxing incisions but provide less relaxation & have a higher risk of causing significant circulatory compromise
Describe a Z-plasty
- Made adjacent to a wound to reduce tension on the wound & facilitate wound closure
- Parallel to the greatest lines of tension (perpendicular to the incision you are closing)
- 1/3 to 1/2 the length of the incision you are closing
- Cut a 60 degree on “limbs of the Z”
What should be done before a tumor is removed
The skin tension & elasticity should be assessed but excessive tumor manipulation should be avoided
What should be planned before skin tumor surgery
- Direction of skin tension lines
- Shape of the excision
- Method of closure
What should be done for large areas in a skin tumor removal
Clipped & aseptically prepared especially if there is a chance that skin flaps may be needed for closure
What does the excision of skin tumors include
- the tumor
- Previous biopsy sites
- Wide margins of norm tissue in 3D
What should be removed w/ benign tumors
- the tumor
- 1 cm of norm tissue
What should be removed in malignant tumors
- Tumor
- Margin of more than 2 to 3 cm may be necessary for complete local excision ( margins in all dimensions including the deep margin if feasible)
What tumors call for a greater margin distance
- Mast cell tumors
- Melanomas
- Squamous cell carcinomas
- Feline mammary adenocarcinomas
- Hemangiopericytomas
- Infiltrating lipomas
What tissues are resistant to neoplastic invasion & therefore often spared during resection
- Cartilage
- Tendon
- Ligaments
- Fascia
- Other collagen-dense & vascular poor tissue
How many fascial layers below the tumor margins should excision of infiltrative or aggressive tumors extend
At least on fascial layer below
Describe radical tumor excision
- Removal of an entire compartment or structure, amputation, or lobectomy
- Indicated for poorly localized tumors or those w/ high grade malignancy
What should be included in excision of infiltrative or aggressive tumors
- Greater than 2 to 3 cm of norm tissue around the lesion
- Extend the dissection @ least one fascial layer below the tumor margins
Why do local tumors often recur
B/c the surgical margins for the original tumor were inadequate
Describe advancement glaps
- Local subdermal plexus flaps
- Flaps formed in adjacent loose elastic skin that can slid over the defect
- Developed parallel to the lines of least tension
- Single pedicle, bipedicle, H-plasty, V-Y flaps
Describe rotational flaps
- Local flaps that are pivoted over a defect w/ which they share a common border
- Semicircular & may be paired or single
- Used to close triangular defects w/out creating a secondary defect
- The skin is undermined in a stepwise fashion until it covers the defect w/out tension
Describe the steps of rotational flaps
Describe transposition flaps
- Rectangular local flaps that bring additional skin when rotated into defect
- 90 degree transposition flaps are aligned parallel to the lines of greatest tension to get the bulk of the flap to cover the defect
- Width of the flap equals the width of the defect
- Length is determined by measuring from the pivot point of the flap to the most distant point of the defect
Describe interpolation flaps
- Lacks a common border w/ the wound
- Leaves an area of interposed skin btw/ the donor bed & the recipient wound
- Created in the same way as a transposition flap except that the length must include the length of the intervening skin segment
- Sub Q tissue is left exposed
Describe tubed pedical flaps
- Uses a multi staged procedure to “walk” an indirect distant flap to a recipient site
- Advanced procedure performed by a specialist
List the steps of creating tubed pedical flaps
Describe axial pattern flaps
- Include a direct cutaneous artery & vein @ the base of the flap
- Terminal branches supply the subdermal plexus T
- Have better perfusion than pedicle flaps w/ circulation from the subdermal plexus alone
- Flaps are elevated & transferred to cutaneous defects w/in their radius
What direct cutaneous vessels are used in axial pattern flaps
- Caudal auricular
- Omocervical
- Thoracodorsal
- Caudal superficial epigastric
- Medial genicular
- Deep circumflex iliac
- Superficial lateral caudal inset
- Superficial brachial inset
- superficial temporal
Why is a concurrent ovariohysterectomy recommended
B/c transposed glands remain functional
How can skin grafts be meshed
By making small full thickness incisions through the graft
List some skin grafts
- Full thickness grafts
- Sheet grafts
- Plug, punch or seed grafts
- Strip grafts
- Mesh Grafts
- Split thickness skin grafts
