Ch 77 Tension relieving techniques Flashcards
What happens to a wound under excessive tension?
Tissue ischaemia and pressure necrosis will result, followed by suture cutout and inevitably incisional dehiscense
What determines skin tension?
The predominant pull of the collagen and elastin fibers in dermal and hypodermal tissues
Which area of the body are most at risk of shear stresses at a wound edge?
Highly mobile areas
- Axilla
- Inguinal area
- Over joints
- Tail base
- Foot pad lacerations
- COmmisure of the lip
highly mobile areas are subject to shear
tension lines
incision should be parallel to the tension lines, thus allowing any tension on the final sutured incision to be aligned with the long axis of the incision rather than across it.
What components of the skin are central to its ability to be mobilised / its viscoelastic nature?
Collagen fibers
Elastin fibers
Lubricating extracellular matrix
decision making factors
wound factors
- size, shape,
- anatomic location,
- chronicity,
- wound bed condition
- status of the periwound skin
- bacterial load
animal factors
- species,
- breed,
- age,
- temperament
- concurrent injuries, conditions
owner factors
- financial capabilities,
- compliance, and commitment
List Halsteads Principles
DoGBAATH
Strict aseptic technique
Gentle tissue handling
Meticulous haemostasis
Preservation of blood supply
Obliteration of dead space
Accurate apposition of tissue planes
Minimisation of** tension** on tissue
goals for recon
- minimize tension and motion of the primary suture line (to optimize wound healing)
- return function to the area (by providing protection and full range of motion)
- ensure the final outcome is free of ongoing morbidity (by restoring full-thickness coverage of pliable skin)
list tension relieveing techniques (6)
- undermining
- tension reliveing sutures/stents
- skin stretching
- incisional NWPT
- relaxing incisions
- plasty
When present, what layer should undermining be deep to?
The panniculus carnosus layer
- Cutaneous trunci
- Platysma
- Sphincter colli superficialis
Deep to this muscle to preserve the deep subdermal plexus
List some tension-relieving suturing techniques
Strong subcutaneous sutures
Stent or bolster sutures
Far-Near-Near-Far and Far-Far-Near-Near
Walking sutures
Horizontal and vertical mattress
Why are horizontal and vertical matress sutures not recommended as tension relieveing suture techniques?
Horizontal mattress may compromise the blood supply to the wound edge
Vertical mattress does not compromise the blood supply but causes significant eversion of wound edges.
Far-Near-Near-Far and Far-Far-Near-Near are just as functional and more cosmetically acceptable
What materials are NOT recommended as stents?
Buttons and red rubber drains - do not adequately disperse tension and can cut through the skin
List some methods of skin stretching techniques
Pretensioning suture
Posttensioning
Presuturing
Acute Intraoperative Skin Stretching
Chronic skin expansion
What phenomena (2) of skins viscoelasticity are taken advantage of for skin stretching?
- Mechanical creep - elongation under constant short-term loading
- Stress relaxation - Delicate elastic fibers fracture and lose their tendancy to recoil once the load is removed
What structural changes occur to allow for mechanical creep?
Within the extracellular matrix, the convoulter superhelices of the coiled triple helix collagen fibers will readily straighten and realign in a more parallel orientation, releasing water molecules and increasing skin viscosity
List three methods of pretensioning suture application?
How often and for how long should these be tightened prior to wound closure?
- Simple continuous suture line
- Continuous horizontal intradermal running pattern
- Extenally applies skin stretching device (Velcro)
Tightened every 8-24hr for 2-3 days
What can be used to maintain suture tension in pretensioning sutures?
Split shot sinker (used for fishing!)
What suture pattern is used for pre-suturing for skin stretching
Lembert, for plicating the skin over an area of planned excision
What phenomenon does chronic skin expansion take advantage of?
Biological creep - The creation of new dermal and epidermal components following prolonged constant loading
What changes occur in the skin overlying an explandable tissue stretcher?
What is the recommended rate of expansion?
- SQ fat and dermal thickness decrease and epidermal proliferation occurs
- Dense fibrous capsule forms over the expander
- Skin is not as pliable
- However, skin perfusion is enhanced
- Explanded by 10-15% of final volume every 2-3 days
List options of relaxing incisions
- Mesh expansion (1cm incision, 1cm appart in scattered rows)
- Simple relaxing incision (Bipedicle flap), must not exceed 4:1 length-to-width ratio
- V-Y plasty
- Z-plasty
- M-plasty (at 1 or both ends of the end of a fusiform incision)
mesh
simple relaxation
V-Plasty
Z-plasty
used to gain length along the central limb of the plasty (between points x and y)
M-plasty
What is the “half bow-tie technique”?
fudging
What suture is recommended where multiple points of skin come together?
Half-buried mattress suture
List options for closing a large circular defect
- Closed in linear fashion with correction of dog ears
- Revised to fusiform incision and closed
- Divide into three equal arcs and performe three-point closure
- Combined V-plasty
- O- to S-plasty
Outcome of reconstruction of
cutaneous limb defects in dogs
using hygroscopic “self-inflating”
tissue expanders
M. De Lorenzi * ,
12 consecutive cases of reconstruction of distal cutaneous limb defects in dogs.
Devices were removed after a mean of 24 days (range
13 to 42 days). Primary closure was achieved in eight of 11 cases,
All incompletely reconstructed defects or areas of wound dehiscence healed by second intention.
Defects below the carpus and tarsus are more challenging to treat with this method.
1 removed perceived that the implants were disrupting the blood supply
to the leg.
four cases in which dehiscence occurred
