Ch 77 Tension relieving techniques

Question 1

What happens to a wound under excessive tension?

Answer 1

Tissue ischaemia and pressure necrosis will result, followed by suture cutout and inevitably incisional dehiscense

Question 2

What determines skin tension?

Answer 2

The predominant pull of the collagen and elastin fibers in dermal and hypodermal tissues

Question 3

Which area of the body are most at risk of shear stresses at a wound edge?

Answer 3

Highly mobile areas
- Axilla
- Inguinal area
- Over joints
- Tail base
- Foot pad lacerations
- COmmisure of the lip

highly mobile areas are subject to shear

Question 4

tension lines

Answer 4

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.

Question 5

What components of the skin are central to its ability to be mobilised / its viscoelastic nature?

Answer 5

Collagen fibers
Elastin fibers
Lubricating extracellular matrix

Question 6

decision making factors

Answer 6

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

Question 7

List Halsteads Principles

DoGBAATH

Answer 7

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

Question 8

goals for recon

Answer 8

• 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)

Question 9

list tension relieveing techniques (6)

Answer 9

• undermining
• tension reliveing sutures/stents
• skin stretching
• incisional NWPT
• relaxing incisions
• plasty

Question 10

When present, what layer should undermining be deep to?

Answer 10

The panniculus carnosus layer
- Cutaneous trunci
- Platysma
- Sphincter colli superficialis

Deep to this muscle to preserve the deep subdermal plexus

Question 11

List some tension-relieving suturing techniques

Answer 11

Strong subcutaneous sutures
Stent or bolster sutures
Far-Near-Near-Far and Far-Far-Near-Near
Walking sutures
Horizontal and vertical mattress

Question 12

Why are horizontal and vertical matress sutures not recommended as tension relieveing suture techniques?

Answer 12

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

Question 13

What materials are NOT recommended as stents?

Answer 13

Buttons and red rubber drains - do not adequately disperse tension and can cut through the skin

Question 14

List some methods of skin stretching techniques

Answer 14

Pretensioning suture
Posttensioning
Presuturing
Acute Intraoperative Skin Stretching
Chronic skin expansion

Question 15

What phenomena (2) of skins viscoelasticity are taken advantage of for skin stretching?

Answer 15

• 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

Question 16

What structural changes occur to allow for mechanical creep?

Answer 16

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

Question 17

List three methods of pretensioning suture application?
How often and for how long should these be tightened prior to wound closure?

Answer 17

• Simple continuous suture line
• Continuous horizontal intradermal running pattern
• Extenally applies skin stretching device (Velcro)

Tightened every 8-24hr for 2-3 days

Question 18

What can be used to maintain suture tension in pretensioning sutures?

Answer 18

Split shot sinker (used for fishing!)

Question 19

What suture pattern is used for pre-suturing for skin stretching

Answer 19

Lembert, for plicating the skin over an area of planned excision

Question 20

What phenomenon does chronic skin expansion take advantage of?

Answer 20

Biological creep - The creation of new dermal and epidermal components following prolonged constant loading

Question 21

What changes occur in the skin overlying an explandable tissue stretcher?
What is the recommended rate of expansion?

Answer 21

• 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

Question 22

List options of relaxing incisions

Answer 22

• 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)

Question 23

mesh

Question 24

simple relaxation

Question 25

V-Plasty

Question 26

Z-plasty

Answer 26

used to gain length along the central limb of the plasty (between points x and y)

Question 27

M-plasty

Question 28

What is the “half bow-tie technique”?

Answer 28

fudging

Question 29

What suture is recommended where multiple points of skin come together?

Answer 29

Half-buried mattress suture

Question 30

List options for closing a large circular defect

Answer 30

• 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

Question 31

Outcome of reconstruction of
cutaneous limb defects in dogs
using hygroscopic “self-inflating”
tissue expanders
M. De Lorenzi * ,

Answer 31

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