Large breed dogs present a specific wound closure challenge: when skin is removed or lost over the trunk, there is often not enough laxity to simply pull the edges together. Pulling too hard creates tension. Tension causes ischemia. Ischemia causes dehiscence.

Walking sutures solve this by redistributing the tension before the skin edges ever come together.

Quick answer: Walking sutures are subcutaneous sutures that anchor the dermis to the underlying fascia at intervals along a wound, advancing skin progressively toward the defect with each placement rather than attempting to close the full gap in one pull. DVM360 (Swaim) describes them as "tension-type sutures that can be used to close large skin defects in areas where sufficient skin surrounds the wound." Standard material: 2-0 PDS or Biosyn (3-0 in patients under 15 kg). Particularly indicated for trunk and lateral thorax wounds in large dogs.

Key takeaways

• Walking sutures anchor dermis to fascia at intervals, advancing skin progressively toward the wound center.
• Primary indication: large trunk and lateral thorax skin defects in dogs where direct closure would create excessive tension.
• Standard material: 2-0 PDS or Biosyn; 3-0 in patients under 15 kg.
• Staggered removal protocol: remove every other suture at day 10, remaining sutures at day 14.
• Thorax wounds require respiratory monitoring tight closure can impair breathing in smaller patients.
• Not appropriate over skin flaps walking sutures risk damaging the blood supply to the flap.

What walking sutures do

A walking suture does not close the wound at the skin surface. It anchors the dermis to the fascia beneath the skin, pulling the skin toward the defect from underneath.

DVM360 (Dr. Steven Swaim, reconstructive surgery techniques): "Walking sutures are tension-type sutures that can be used to close large skin defects in areas where sufficient skin surrounds the wound that can be moved or stretched to close the wound. These sutures are primarily indicated for closing skin defects on the trunks of small animals."

Veterinary Surgery Online: "Walking sutures can be used to tack down the dermis to the underlying fascia. These also help decrease tension on the wound edges. After placement, the wound edges should be in close proximity and under minimal tension."

Each walking suture placed advances the skin a small distance. Placed sequentially from the wound edges inward, they bring the skin incrementally closer to the defect center with each stitch hence "walking" the skin across.

When walking sutures are used

Primary indication: large trunk skin defects

• Mass excisions on the lateral thorax or abdomen requiring wide margins
• Degloving injuries where skin was lost over the trunk
• Wounds too large for simple closure but with adequate adjacent skin for advancement
• Cases where a skin flap or graft is not available or not planned

DVM360 (Swaim): "Most large skin defects on the trunks of dogs and cats can be closed with walking sutures, either using the technique described here or a modification of it. These sutures advance local skin to close large defects without requiring additional incisions to create flaps or attain relaxation."

When walking sutures cannot fully close the wound

If the defect is too large for complete walking suture closure, the technique closes the wound as much as possible, then allows the remainder to heal by second intention or stages it for a secondary surgery.

Veterinary Surgery Online: "If a wound is too large to be closed completely using this technique, it can be closed enough to allow the remainder of the wound to heal by second intention or with a secondary surgery."

Contraindication: skin flaps

Today's Veterinary Practice (Caudal Superficial Epigastric Flap technique notes): "I prefer not to tack down or use walking sutures in the subcutaneous tissues to attempt to reduce motion and dead space under the flap and inguinal region. These sutures could inadvertently damage the blood supply to the flap."

For how tension-relieving sutures are used for high-tension surgical wounds generally, see tension-relieving sutures alongside walking sutures.

Technique overview

Bite placement:

• The needle passes through the dermis on one side of the advancing skin edge
• Then through the superficial fascia at the target location (where that skin edge should end up)
• Tied the skin edge advances to meet the fascia at that point
• The next suture is placed in the adjacent skin, advancing the next section

Pattern sequence:

• Begin at the wound margins and work inward
• Each suture advances one section of skin; sequential sutures advance the whole leading edge
• After all walking sutures are placed, the wound edges should be in close proximity or apposed

Final skin closure:Placed after all walking sutures. Standard options: 3-0 to 4-0 Prolene or nylon (interrupted), or skin staples for speed.

Suture material for walking sutures

Veterinary Surgery Online: "Typically, walking sutures and muscle fascia sutures are applied using 2-0 PDS or Biosyn (3-0 in patients under 15 kg, or occasionally 0 in larger dogs). Subcutaneous tissues closed using 3-0 PDS, Biosyn, or Monocryl (4-0 in smaller patients). Dermal closure performed using 3-0 Monocryl or Biosyn (4-0 in smaller patients)."

PDS and Biosyn are monofilament absorbable materials with adequate strength retention for the 3 to 4 weeks needed while the tissue planes adhere and the skin advances fully. They are preferred over braided absorbable materials in the subcutaneous plane because of lower infection risk.

For how suture size relates to patient weight in this context, see suture size selection for walking sutures.

Thorax wounds: a specific caution

Tight closure of thorax skin restricts the chest wall's ability to expand. DVM360 (Swaim): "Keep in mind that tight skin closure on the thorax can impair respiration, especially in smaller animals. Therefore, thorough preoperative assessment and special care during closure should be taken to avoid this complication."

This is most relevant in patients under 10 to 15 kg and in wounds over the mid-lateral or dorsal thorax. The surgeon must assess respiratory function after closure and before recovery from anesthesia.

Suture removal protocol

Walking sutures use a staggered removal schedule to prevent the wound from reopening as tension redistributes during healing:

DVM360 (Swaim): "Remove every other suture (half the sutures) 10 days after surgery. Remove the remaining sutures after 14 days."

This staggered approach maintains some mechanical support while allowing the earlier-placed sutures to be assessed. If the wound looks precarious at day 10, the vet may delay removing any sutures at that visit.

For how suture removal timing applies to walking suture cases, see suture removal timing in high-tension closures.

What to monitor at home

Days 1 to 10:

• Swelling or firmness along the suture line is normal as the skin advances and adheres
• Discharge should be minimal serosanguinous (slightly blood-tinged watery) discharge is expected in small amounts; purulent or copious discharge is not
• The wound line may look "bunched" immediately after surgery this is expected as the skin advances and will flatten during healing

Signs requiring contact with your vet:

• Wound edges separating
• Increasing redness extending beyond the wound margins
• Wound discharging pus
• Patient showing respiratory changes (for thorax wounds)

For how dead space management intersects with walking suture technique, see dead space management alongside walking sutures. In obese dogs, walking sutures are especially valuable for managing the thick subcutaneous fat layer; see walking sutures in obese dog closure.

Frequently asked questions

My large dog had a mass removed and the vet used "walking sutures." Why not just standard sutures?

Standard closure sutures are placed at the skin surface and close the gap by pulling the edges together. In large wounds, that pull creates ischemia-inducing tension. Walking sutures move the skin toward the gap at the subcutaneous level first, so by the time skin closure sutures are placed, the edges are already close together and under minimal tension.

Are walking sutures the same as tension sutures?

Related but not identical. Walking sutures advance skin by anchoring dermis to fascia progressively. Tension-relieving sutures (mattress, far-near-near-far) redistribute tension across a wider surface area of an existing closure. Both reduce tension but through different mechanisms and at different stages of wound closure.

The wound looks wrinkled and bunched after my dog's surgery. Is that a problem?

Not usually. When skin is advanced toward a defect using walking sutures, the surrounding skin gathers slightly before it redistributes. This bunching typically resolves over 5 to 10 days as the skin stretches and adheres. If the wrinkling is accompanied by redness, warmth, or discharge, contact your vet.

Walking sutures do something the skin surface cannot: they move the wound edges before the skin is asked to span a gap under tension. In large breed dogs with significant trunk defects, they are the difference between a closure that holds and one that dehisces in the first week.

Resources

• DVM360 (Dr. Steven Swaim). Skills Laboratory: Reconstructive Surgery Techniques, Part 5: Walking Sutures. dvm360.com
• Veterinary Surgery Online. Wound Closure Continued. vetsurgeryonline.com
• Today's Veterinary Practice. Caudal Superficial Epigastric Flap. todaysveterinarypractice.com
• WSAVA 2007 (VIN). Reconstructive Surgery. vin.com

High-tension wounds are not just technically harder to close they fail by a different mechanism than standard wounds. The force that causes problems is not bacterial but mechanical: the skin pulls apart before tissue healing has created intrinsic strength to replace the suture.

Understanding how surgeons address this before closure begins is the key to understanding what your dog's procedure involved and what to watch for during recovery.

Quick answer: High-tension closure in dogs addresses the underlying tension problem before or alongside placing skin sutures. The main techniques are: undermining (freeing skin from underlying tissue to mobilize it), walking sutures (advancing skin subcutaneously toward the defect), tension-relieving suture patterns (horizontal mattress, vertical mattress, far-near-near-far), and releasing incisions or skin flaps (for defects that cannot be closed with the skin available). Pre-surgical tension assessment with the dog in standing position is essential wounds that look closable under anesthesia may be too tight once the dog is ambulatory.

Key takeaways

• Assess tension before the skin is incised, not after assess with the dog standing if possible.
• Undermining frees skin from underlying tissue to provide additional reach without requiring skin from elsewhere.
• Walking sutures advance skin toward the defect at the subcutaneous level before skin closure begins.
• Tension-relieving suture patterns (horizontal mattress, NFFN) distribute load across more tissue.
• Releasing incisions create parallel cuts in adjacent skin to allow closure without tension on the primary wound.
• Staples are not recommended over high-tension incisions they deform and open under prolonged tension.

Why tension causes wound failure

When skin edges are pulled together under more force than the tissue can support at the suture entry points, two things happen:

• Sutures cut through: the suture loop creates a linear tear perpendicular to the wound line at each entry point
• Ischemia at wound margins: compression from tight sutures reduces blood flow to the tissue between the entry points and the wound edge

MSPCA-Angell (Incisional Tension Relief: Simple Intraoperative Options): "From my clinical experience, the caudal-lateral thigh region is prone to dehiscence when the surgeon does not properly assess the skin tension prior to surgery. In this region, skin tension is best assessed with the dog standing on the rear legs. When standing, the muscles contract and exert tension to the overlying skin. In contrast, when the patient is under anesthesia, the muscles relax and the skin may appear deceptively pliable."

The practical consequence: a wound closed under anesthesia with apparent adequate skin can dehisce once the dog is ambulatory and muscle tension is restored.

Pre-surgical tension assessment

The standing test: for limb and caudal body wounds where muscular tension significantly affects skin mobility, the surgeon or technician assesses skin mobility before anesthesia with the dog weight-bearing.

The pinch test: at the proposed excision site, two fingers approximate where the wound edges would sit post-closure. If the skin pulls tight or blanches, tension-relief strategies must be planned before the first incision is made.

MSPCA-Angell: "Prior to surgery, manually assessing the regional skin's natural or inherent elasticity will give the veterinary surgeon an idea of which area(s) of adjacent elastic skin can be recruited to close the surgical defect."

Technique 1: Undermining

Undermining is the first-line tension reduction approach freeing the skin from the underlying subcutaneous tissue and fascia by blunt and sharp dissection, allowing the skin to slide toward the defect.

Veterinary Surgery Online: "Undermining the surrounding tissues may be required to release the skin and allow closure of skin edges without tension. This can be performed in a 360-degree fashion with combination of blunt and sharp dissection. Attempt to preserve arteries and veins, and only undermine as necessary to close the wound."

Key principle: undermine only as much as needed. Excessive undermining creates dead space, which fills with serum and provides a bacterial growth medium. Preserve the subcutaneous blood vessels that supply the skin flap created by undermining devascularized skin dies.

Technique 2: Walking sutures

Walking sutures anchor the dermis to the fascia at intervals, advancing the skin progressively toward the defect at the subcutaneous level. By the time skin closure sutures are placed, the edges are already close together with minimal remaining tension.

Veterinary Surgery Online: "Walking sutures can be used to tack down the dermis to the underlying fascia. These also help decrease tension on the wound edges. After placement, the wound edges should be in close proximity and under minimal tension."

Material: 2-0 PDS or Biosyn for the walking sutures themselves (3-0 in patients under 15 kg).

For full walking suture technique detail, see walking sutures for large skin defects.

Technique 3: Tension-relieving suture patterns

When skin edges can be approximated but closure tension is high, tension-relieving patterns distribute the load across more tissue surface area.

Horizontal mattress: placed parallel to the wound, distributing tension 8 to 10 mm from each edge. Can be used as a temporary stay stitch, then removed after 3 to 4 days once the appositional closure is secure.

Vertical mattress: takes a deep bite far from the wound edge, returns with a shallow bite close to it. Provides deep tissue purchase and everts the wound edges important in high-tension wounds that tend to invert.

Far-near-near-far (FNFN): appositional and tension-relieving simultaneously. Stays in through full healing. Appropriate when both cosmesis and tension distribution are required.

What to avoid: simple interrupted sutures alone across a high-tension wound. They cannot distribute the load adequately and are the most common pattern associated with suture cut-through.

For the full tension-relieving suture pattern guide, see tension-relieving patterns for high-tension wounds.

Technique 4: Releasing incisions

When neither undermining nor tension-relief patterns provide enough skin to close the primary defect, a parallel incision is made in adjacent skin. This incision relaxes the full skin sheet, allowing the primary wound to close without tension.

The releasing incision itself is left to heal by second intention (contraction and epithelialization). Releasing incisions are most useful in:

• Trunk and lateral body wounds
• Wounds where linear advancement of adjacent skin is adequate

DVM360: "Releasing incisions, advancement and rotational flaps, or punch grafts can be used to close difficult wounds."

Technique 5: Skin flaps

When the defect is too large for any of the above approaches, a skin flap recruits skin from an adjacent or distant region. The flap maintains its blood supply through a pedicle attachment.

Advancement flap: the adjacent skin is incised and slid forward to fill the defect without rotation.

Rotation flap: a semicircular area of skin is rotated on a pivot point to fill a triangular or irregular defect.

Transposition flap: skin is moved from an adjacent or nearby area by creating a pedicle.

MSPCA-Angell: "For more challenging defects in this area, a transposition flap can effectively close the surgical defect and eliminate the risk of tension-induced dehiscence."

For how high-tension wound closure management compares to error-prone closure, see high-tension errors in wound closure. In obese dogs, high skin tension combines with poor wound vascularity to make these techniques especially critical; see high-tension closure in obese dogs.

Skin staples in high-tension wounds: a specific caution

MSPCA-Angell makes an important clinical observation: "It is the author's experience to avoid the use of skin staples to close incisions under tension. There is a risk that the staples will deform and open when subject to prolonged incisional tension."

Skin staples are appropriate for standard-tension wounds but are mechanically inferior to sutures in sustained high-tension situations. Use vertical or horizontal mattress sutures instead, potentially supplemented by walking sutures for the subcutaneous layer.

What to monitor at home

High-tension wounds carry more post-operative risk than standard closures. Owner monitoring is more important, not less.

Check twice daily:

• Suture lines remaining intact with no cut-through (look for linear tears at suture entry points)
• No gap opening between sutures
• No purulent or foul-smelling discharge
• Swelling progressing to decrease, not increase, after day 3 to 4

Activity restriction is non-negotiable: every movement applies tension to the closure. Even brief unsupervised activity can open a closure that held through the first several days. Leash-only, calm walks only until the recheck.

For the post-operative monitoring protocol applicable to high-tension wounds, see post-op monitoring after high-tension closure.

Frequently asked questions

My dog had a large tumor removed and the vet mentioned using a "flap." Does that mean the wound is more serious?

A flap is a technique, not a complication. It means the tumor was large enough that adjacent skin needed to be recruited to close the defect without tension. Flap closures heal very well when the flap's blood supply is preserved during surgery. The extra complexity is in the operating room; the recovery is not necessarily harder than a standard closure.

The wound looks tight and bunched after surgery. Is that normal?

Some gathering or bunching at the wound is expected when skin has been advanced toward a defect. This redistributes as the skin stretches slightly and the subcutaneous adhesions form over the first 5 to 10 days. If the bunching is accompanied by pale or dark discoloration at the wound edge, contact your vet that can indicate vascular compromise.

Can tension-related dehiscence be repaired?

Yes, often. If caught within 24 to 48 hours of opening, the wound can be re-closed after debridement of the edges. If the wound has been open long enough for infection to establish, delayed primary or secondary closure protocols apply. The key is calling your vet the same day the wound opens, not waiting.

High-tension wounds require planning before the first incision, not problem-solving after the last suture. The techniques that manage tension successfully all work by reducing the load before asking the skin to bear it through mobilization (undermining), advancement (walking sutures), load distribution (tension-relieving patterns), or supplemental skin recruitment (releasing incisions and flaps).

Resources

• MSPCA-Angell. Incisional Tension Relief: Simple Intraoperative Options. mspca.org
• Veterinary Surgery Online. Wound Closure Continued. vetsurgeryonline.com
• DVM360. Wound Management: Proceedings. dvm360.com
• Veterian Key. Selection of Suture Materials, Suture Patterns, and Drains for Wound Closure. veteriankey.com

Intradermal closure in dogs is a surgical technique used to close skin wounds with minimal scarring and faster healing. This method places sutures within the skin layers, avoiding external stitches that can irritate your dog or require removal. Understanding intradermal closure helps you make informed decisions about your pet's surgical care.

This article explains what intradermal closure is, how it works, its advantages, and how to care for your dog after surgery. You will learn about the materials used, common techniques, and potential complications to watch for during recovery.

What is intradermal closure in dogs?

Intradermal closure is a suturing technique where stitches are placed inside the skin layers, specifically within the dermis. This method hides the sutures beneath the skin surface, reducing irritation and improving cosmetic outcomes. It is commonly used in veterinary surgery for skin incisions and lacerations.

The goal is to bring the skin edges together securely while minimizing external suture exposure. This technique helps wounds heal with less inflammation and reduces the risk of infection or self-trauma by the dog.

• Hidden sutures: Sutures are placed beneath the skin surface, preventing your dog from licking or scratching them, which promotes safer healing.
• Cosmetic benefit: Intradermal closure results in less visible scarring compared to traditional external stitches, improving your dog's appearance after surgery.
• Reduced suture removal: Because sutures are buried, they often do not require removal, reducing stress for both you and your dog.
• Secure wound closure: This technique provides strong wound edge apposition, which helps prevent wound opening and infection.

Intradermal closure is a preferred method in many veterinary surgeries due to these benefits. It requires skill and appropriate suture materials to ensure success.

How is intradermal closure performed in dogs?

The procedure involves placing a continuous or interrupted suture pattern within the dermis layer of the skin. The surgeon carefully aligns the wound edges and uses absorbable sutures to close the incision beneath the surface.

Proper technique is essential to avoid tension on the skin and to ensure the wound edges heal evenly. The choice of suture material and needle type also affects the outcome.

• Suture placement: Sutures are inserted horizontally or vertically within the dermis to bring skin edges together without external exposure.
• Absorbable sutures: Materials like poliglecaprone or polydioxanone are used, which dissolve over time, eliminating the need for removal.
• Needle type: A reverse cutting needle is often preferred to minimize tissue trauma during suture placement.
• Continuous pattern: A running intradermal suture provides even tension distribution and faster closure compared to interrupted stitches.

After suturing, the skin surface appears smooth with no visible stitches. This technique requires careful handling to avoid puckering or uneven closure.

What are the benefits of intradermal closure for dogs?

Intradermal closure offers several advantages over traditional external suturing methods. These benefits improve healing, reduce complications, and enhance cosmetic results for your dog.

Understanding these benefits can help you discuss surgical options with your veterinarian confidently.

• Less irritation: Buried sutures prevent your dog from chewing or scratching the wound, reducing inflammation and discomfort.
• Improved healing: The technique promotes better skin edge alignment, which supports faster and stronger wound healing.
• Lower infection risk: With no external suture exposure, there is less chance for bacteria to enter the wound site.
• Better appearance: The cosmetic outcome is superior, with minimal scarring and no visible stitches after healing.

These benefits make intradermal closure a preferred choice for elective surgeries and wounds in dogs, especially in visible areas like the face or limbs.

When is intradermal closure recommended for dogs?

Veterinarians choose intradermal closure based on the wound type, location, and patient factors. It is most suitable for clean, straight incisions where cosmetic outcome is important.

Not all wounds are ideal for this technique, so your vet will assess the situation before deciding.

• Clean surgical incisions: Intradermal closure is ideal for planned surgeries with minimal contamination risk.
• Superficial wounds: Wounds involving only the skin layers without deep tissue damage are good candidates.
• Areas needing cosmetic care: Locations like the face, neck, or limbs benefit from less visible scarring.
• Stable patients: Dogs that can tolerate anesthesia and have no skin infection are suitable for this closure method.

Your veterinarian will evaluate your dog's specific case to determine if intradermal closure is the best option.

What materials are used for intradermal closure in dogs?

Choosing the right suture material is crucial for successful intradermal closure. Absorbable sutures are preferred to avoid the need for removal and reduce irritation.

The needle type also affects how easily the sutures pass through the skin and how much tissue damage occurs.

• Poliglecaprone sutures: These absorbable sutures dissolve within 90-120 days and cause minimal tissue reaction.
• Polydioxanone sutures: Longer-lasting absorbable sutures that maintain strength for several weeks, ideal for slow-healing wounds.
• Reverse cutting needles: Designed to cut through tough skin with less trauma, improving suture placement accuracy.
• Monofilament sutures: Smooth, single-strand sutures reduce bacterial colonization and tissue drag during closure.

Your veterinarian selects materials based on wound characteristics and healing needs to optimize outcomes.

How should you care for your dog after intradermal closure?

Proper aftercare is essential to ensure your dog's wound heals well after intradermal closure. You must prevent infection, avoid trauma, and monitor for complications.

Following your vet's instructions carefully will help your dog recover quickly and comfortably.

• Limit activity: Restrict your dog's movement to prevent stress on the wound and avoid suture disruption.
• Prevent licking: Use an Elizabethan collar or other devices to stop your dog from licking or chewing the wound area.
• Keep wound clean: Follow your vet’s advice on cleaning the site gently without soaking or harsh chemicals.
• Watch for signs: Monitor for redness, swelling, discharge, or pain, and contact your vet if these occur.

Most wounds heal within 10-14 days with proper care. Absorbable sutures dissolve on their own, so no removal is needed unless complications arise.

What complications can occur with intradermal closure in dogs?

While intradermal closure is generally safe, some complications can happen. Knowing what to expect helps you act quickly if problems arise.

Early detection and veterinary care can prevent minor issues from becoming serious.

• Wound dehiscence: The wound may reopen if sutures fail or if your dog stresses the area excessively.
• Infection risk: Though lower than external sutures, infections can still occur and require prompt treatment.
• Allergic reaction: Some dogs may react to suture materials, causing redness or swelling.
• Excessive scarring: Improper technique or healing can lead to thick or raised scars, affecting appearance and function.

If you notice any unusual changes in your dog's wound, contact your veterinarian immediately for assessment and care.

Conclusion

Intradermal closure in dogs is a valuable surgical technique that offers strong wound closure with minimal scarring and less irritation. It uses absorbable sutures placed beneath the skin surface, improving healing and cosmetic results.

Understanding how this method works, when it is recommended, and how to care for your dog afterward helps ensure the best recovery. Always follow your veterinarian’s advice and watch for any signs of complications to keep your dog safe and comfortable.

FAQs

Is intradermal closure painful for dogs?

The procedure itself is painless due to anesthesia during surgery. Postoperative discomfort is usually mild and manageable with pain medication prescribed by your vet.

How long do intradermal sutures last in dogs?

Absorbable intradermal sutures typically dissolve within 10 to 14 days, depending on the suture material and your dog’s healing rate.

Can intradermal closure be used on infected wounds?

Intradermal closure is generally not recommended for infected or heavily contaminated wounds, as buried sutures may trap bacteria and worsen infection.

Do dogs need a cone after intradermal closure?

Yes, an Elizabethan collar is usually recommended to prevent licking or chewing the wound, which can disrupt sutures and delay healing.

When should I contact my vet after intradermal closure?

Contact your vet if you notice redness, swelling, discharge, foul odor, or if your dog shows signs of pain or the wound opens unexpectedly.

Fascia is the connective tissue that wraps, separates, and supports muscles and organs. It does not get much attention as a tissue type, but it is the primary holding layer in most veterinary wound closures.

When the linea alba is sutured after abdominal surgery, what is actually being closed is fascia. When a joint capsule is repaired after orthopedic surgery, fascia is doing the structural work. Getting fascial closure wrong leads to hernia, dehiscence, or implant failure complications that require return surgery.

Quick answer: Fascial closure uses absorbable monofilament sutures (PDS or Vicryl, size 0 to 3-0 depending on patient size) placed in a simple continuous or interrupted pattern that incorporates adequate tissue bites (4 to 10 mm). The key principle is that sutures must engage the fascia itself, not just adjacent muscle or fat. Fascia is the holding layer it has the tensile strength muscle belly and fat tissue lack.

Key takeaways

• Fascia is the primary tensile-holding layer in most abdominal and orthopedic wound closures.
• Sutures must engage the fascia itself, not surrounding muscle belly or fat tissue.
• PDS is the preferred material for fascial closure because of its long strength retention profile.
• Simple continuous pattern is the standard for most fascial closures in small animals.
• Interrupted pattern is used when contamination or poor tissue quality raises continuous failure risk.
• Incisional hernia is the most serious complication of inadequate fascial closure.

What fascia is and why it matters

Fascia is a dense, fibrous connective tissue made primarily of collagen. Unlike muscle, fat, or loose connective tissue, fascia resists tension. When sutures are placed in it, they hold.

In veterinary surgery, the most commonly encountered fascial structures requiring closure:

Understanding which fascial structure is being closed helps explain why suture selection and bite size are procedure-specific.

The critical rule: sutures must engage fascia

Veterian Key (Surgery of the Abdominal Cavity) is explicit: "Because the holding layer of abdominal incisions consists of fascia rather than muscle, dehiscence is common if the rectus fascia is not incorporated in sutures."

This is the most common technical error in fascial closure: placing sutures in the muscle belly adjacent to the fascia rather than through the fascia itself. The consequence is predictable the sutures pull through the non-holding tissue and the wound fails.

Technical guidance:

• Incorporate 4 to 10 mm of fascia in each bite
• Ensure the needle actually passes through the white fibrous tissue, not the adjacent muscle
• In the linea alba, the European Hernia Society recommends a 5 mm suture bite-to-stitch interval as optimal for small animals (supported by published feline cadaver research)

For how fascial closure fits within muscle layer closure, see muscle layers closed alongside fascia.

Suture materials for fascial closure

Why PDS is preferred:

Fascial healing is slow. The linea alba regains meaningful tensile strength over 4 to 6 weeks. PDS maintains strength through that entire period before losing tensile capacity. Vicryl's faster absorption may leave the closure unsupported before full healing occurs in larger patients.

For how suture material selection affects fascial closure outcomes, see suture selection for fascial closure.

Suture patterns for fascial closure

Simple continuous (standard)

The preferred pattern for most fascial closures in small animals. Published data on canine linea alba closure (Rosin and Crowe, 530 coeliotomies) found a complication rate of just 0.19% with simple continuous technique.

Properties:

• Distributes tension evenly along the entire closure length
• Faster than interrupted
• Relies on two secure end knots for integrity

Simple interrupted

Used when the risk of continuous pattern failure is elevated:

• Contaminated or infected wounds
• Poor tissue quality from chronic steroid use, malnutrition, or disease
• Cases where post-operative activity compliance is uncertain (some surgeons use 2-0 suture with interrupted pattern in these cases, per WCVM guidance)

Mattress patterns (tension-relieving)

Horizontal or vertical mattress sutures distribute tension over a wider tissue area and are used when standard bite size is insufficient to achieve tension-free apposition.

For a full discussion of tension-relieving applications, see tension relief during fascial closure.

Fascial closure in specific contexts

Abdominal surgery

The linea alba is the only fascial structure requiring closure for a standard ventral midline celiotomy. The muscle bellies of the rectus abdominis are not closed only the fibrous sheath (the fascia) is incorporated.

Bite size: 4 to 10 mm of fascia per bite. Bites placed every 4 to 8 mm apart. Suture should be taut but not strangulating.

Orthopedic surgery

Joint capsule closure is the functional equivalent of fascial closure for orthopedic procedures. The joint capsule is dense fibrous tissue that must be closed securely to restore joint stability and prevent fluid leakage.

PDS or Vicryl in interrupted or continuous patterns are used. The suture must engage the capsule tissue, not the surrounding soft tissue.

High-tension wounds

When the fascial edges are difficult to appose without excessive tension, a far-near-near-far (tension-relieving) pattern or pre-placed sutures may be used to bring edges into contact before final closure.

For how high-tension closures are managed at the fascial level, see high-tension closure techniques for fascia.

Complications of inadequate fascial closure

Incisional hernia: the most serious consequence. Abdominal contents push through the fascial gap. Visible as a soft, reducible bulge at the incision line. Requires surgical repair.

Wound dehiscence: fascial failure at depth causes the wound to separate, potentially opening the abdominal cavity to contamination.

Joint instability: inadequate joint capsule closure allows abnormal joint movement, effusion, and impaired healing after orthopedic procedures.

Seroma at fascial level: when fascial edges do not appose, fluid accumulates in the potential space between them, even if subcutaneous closure above has been performed.

For how fascial closure integrates into the full layered technique, see fascial layer within layered closure.

Frequently asked questions

Can my dog develop a hernia even though the skin closure looks fine?

Yes. The skin heals independently of the fascial layer. A dog can have a healed skin incision with a fascial hernia forming beneath it. New soft swelling at an incision site weeks after skin suture removal should be evaluated by your vet, as it may represent an early incisional hernia.

What does "incorporating fascia" mean in practical terms for a surgeon?

The surgeon can see the difference between white fibrous fascial tissue and the adjacent reddish muscle belly or yellow fat. The needle must visibly pass through the white tissue on both sides of the incision. When it does, the suture has the holding power it needs. When it does not, the suture will eventually fail under tension.

Is fascial closure more important in large dogs than small ones?

It is equally important in all patients, but the consequences of failure are proportionally more significant in large dogs. A large dog's body weight applies more tension to the fascial repair. Large breeds are also more active during recovery, further stressing the closure. This is why suture size scales up with patient size.

Fascial closure is where wound integrity is actually built. The skin may heal on its own given enough time, but the fascial layer does not. When fascia is properly engaged with the right material and an adequate tissue bite, the wound has a structural foundation that holds through the entire healing period. When it is not, the foundation is absent and the consequences appear weeks later.

Resources

• Veterian Key. Surgery of the Abdominal Cavity. veteriankey.com
• WCVM University of Saskatchewan. Lab 6 Part 4: Incision Closure. wcvm.usask.ca
• Veterinary Evidence. Choice of Suture Pattern for Linea Alba Closure. veterinaryevidence.org
• Veterian Key. Suturing Techniques and Common Surgical Procedures. veteriankey.com

Wound closure isn't just about pulling edges together. The way tissue edges meet determines how cells migrate across the wound, how tension is managed, and what the healed surface looks like.

Veterinary surgeons choose between two main approaches for skin closure: appositional patterns that align edges level with each other, and everting patterns that turn the edges slightly outward. The choice depends on the tissue, the wound, and the outcome desired.

Quick answer: Appositional patterns (simple interrupted, simple continuous, intradermal) bring skin edges level with each other for optimal epithelialization and cosmetic results. Everting patterns (horizontal mattress, vertical mattress, cruciate) turn the edges slightly outward, distributing tension over a larger tissue bite, and are used for high-tension wounds or fragile skin. Appositional patterns are standard for most small animal skin closures. Everting patterns are used when tension would cause an appositional pattern to cut through the tissue.

Key takeaways

• Appositional patterns align wound edges flush for smooth healing and best cosmetic outcome.
• Everting patterns turn edges outward to distribute tension over a larger area of tissue.
• Simple interrupted sutures are the most widely used appositional pattern in small animal surgery.
• Horizontal and vertical mattress sutures are the primary everting patterns used in veterinary surgery.
• Cruciate (cross) sutures offer a hybrid: tension distribution with appositional-quality edge contact.
• Inverting patterns are reserved for hollow organ closure (intestine, bladder) and not used in skin.

Understanding the three pattern categories

Veterian Key (Selection of Suture Materials, Suture Patterns, and Drains) defines the classification:

"Suture patterns are classified as appositional, everting, inverting, or tension-relieving by the way they overcome tension that may disrupt accurate approximation."

For skin wound closure in dogs and cats, three categories matter:

Inverting patterns are not discussed here because they have no role in skin closure.

Appositional patterns: the standard for skin closure

Appositional patterns produce the smoothest healing because the epidermal cells are already aligned. Migration across the wound happens efficiently when edges are level.

University of Melbourne Virtual Vet Surgery states: "Optimal healing comes with appositional patterns as the cells are already lined up and ready to join."

Simple interrupted

The workhorse of small animal skin closure. Individual sutures placed 4 to 8 mm apart, each tied separately.

Advantages:

• Failure of one suture does not compromise the rest
• Easy to adjust tension individually at each stitch
• Allows partial opening for drainage if infection develops

Disadvantages:

• More time-consuming than continuous patterns
• More knots to place and remove

For skin closure methods including where simple interrupted fits within the full range, see closure patterns within skin closure options.

Simple continuous

A running stitch from one end of the wound to the other. Faster than interrupted but the entire line depends on the end knots.

Best for: long, linear wounds in cooperative patients under reliable activity restriction.

Intradermal (subcuticular)

Technically appositional: the pattern runs horizontally through the dermis, bringing edges together from within. No external material is exposed.

For full intradermal technique details, see intradermal closure as a related technique.

Everting patterns: when tension demands more tissue purchase

Everting sutures take a wider and deeper bite of tissue than simple interrupted patterns. This distributes tension over a larger volume of dermis, reducing the risk of the suture cutting through thin or friable skin.

University of Minnesota (Large Animal Surgery notes) states: "In thin skin and wounds under a mild degree of tension, everting techniques, such as horizontal mattress and vertical mattress sutures may be used. Slight eversion of the skin edges is preferable to inversion in respect to wound healing."

When everting patterns are indicated:

• High-tension wounds where simple interrupted sutures would pull through
• Fragile skin (geriatric dogs and cats, immunocompromised patients, those on long-term steroids)
• Wounds with significant subcutaneous dead space contributing to surface tension
• Large breed dogs following mass removal where skin is stretched to cover the defect

Horizontal mattress suture

The most common everting pattern in small animal surgery. The needle enters, crosses the wound, exits on the far side, then returns parallel to create a "U" shape anchored by a single knot.

Properties:

• Distributes tension over 2 to 3 cm of tissue (vs. 4 to 8 mm for simple interrupted)
• Creates mild eversion of wound edges
• Reduces ischemia risk compared to vertical mattress in most cases

For how mattress sutures are used specifically in high-tension wounds, see mattress sutures as everting patterns.

Vertical mattress suture

Placed perpendicular to the wound. Takes a far-near-near-far bite that incorporates deep dermis on both passes.

Properties:

• Better dead space elimination than horizontal mattress
• More tissue ischemia risk if tied too tightly
• Useful when the wound has both tension and dead space concerns

Cruciate (cross) pattern: appositional tension relief

The cruciate pattern sits between appositional and everting categories. It uses a figure-8 configuration: two bites crossing the wound, with the crossing point at the skin surface.

Key properties:

• Distributes tension over more tissue than simple interrupted
• Provides appositional-quality skin edge contact when placed correctly
• More efficient than simple interrupted: WCVM notes "cruciates are a more efficient closure pattern than simple interrupteds"
• Often used for non-linear wounds or as drainage sutures

For cruciate suture applications in dog and cat skin closure, see cruciate pattern as a closure option.

Choosing the right pattern: decision framework

For how tissue type beyond skin determines pattern selection throughout the wound, see tissue type as a guide for pattern selection.

Common errors in pattern selection

Selecting the wrong pattern for a wound's tension level is one of the most consequential closure errors in small animal surgery:

• Using simple interrupted in a high-tension wound: sutures pull through the skin edge, causing wound dehiscence
• Over-tightening a vertical mattress: excess compression cuts off blood supply and causes skin necrosis under the suture
• Using everting patterns in low-tension wounds: unnecessary and creates mild cosmetic irregularity

For a full list of closure errors including pattern-related mistakes, see errors in pattern selection.

Frequently asked questions

How can I tell if my dog's sutures are the right type from looking at them?

External sutures crossing the wound perpendicular to the incision line are typically simple interrupted or cruciate patterns. If the sutures run parallel to the wound with loops on each side, they are mattress sutures. Intradermal closure shows no external sutures at all. Your vet can describe exactly what was placed if you ask.

Can a wound switch from an appositional to an everting pattern if healing doesn't go well?

Not directly. If tension problems develop during healing (edges pulling apart), your vet may need to re-suture using a pattern with better tension distribution. This is one reason rechecks are important: early tension problems caught at day 5 are much easier to address than a fully dehisced wound at day 10.

Do some breeds need everting patterns more than others?

Yes. Breeds with thin, loose skin (Shar Peis, Chinese Crested, some Terrier breeds) or very old dogs on long-term steroids have skin that tears easily under tension. Sighthound breeds have notoriously thin skin and often benefit from mattress patterns for elective surgeries. Your vet will assess your dog's skin quality before selecting a closure pattern.

Pattern selection is one of those surgical decisions that looks simple from the outside and involves considerable judgment. The choice between appositional and everting comes down to a single question: will this tissue hold a simple suture without tearing? When the answer is yes, appositional patterns deliver the best healing. When the answer is no, everting patterns provide the tension distribution the tissue needs.

Resources

• Veterian Key. Selection of Suture Materials, Suture Patterns, and Drains for Wound Closure. veteriankey.com
• University of Minnesota. Suturing: Skin Closure (Large Animal Surgery). open.lib.umn.edu
• WCVM University of Saskatchewan. Lab 6 Part 4: Incision Closure. wcvm.usask.ca
• University of Melbourne Virtual Vet Surgery. Wound Closure. lms.vet.unimelb.edu.au

Not every wound can be fully closed at surgery. When dead space is too large to eliminate with sutures alone, when fluid accumulation is inevitable, or when infection is already present, a drain changes the closure strategy entirely.

Understanding what drains are, when they are placed, and what they need from you at home makes the difference between a drain that works as intended and a complication.

Quick answer: Surgical drains are placed when dead space cannot be fully eliminated by suturing alone, when significant fluid production is expected post-operatively, or when infection is present and drainage is part of treatment. The two main types are Penrose drains (passive, gravity-dependent) and Jackson-Pratt drains (active, suction-based). Most drains are removed in 2 to 5 days. They require a protective bandage at all times and prevent self-trauma from the dog.

Key takeaways

• Drains are placed when sutures cannot fully eliminate dead space or manage expected fluid output.
• Penrose drains are passive: fluid exits by gravity, capillary action, and wound pressure.
• Jackson-Pratt drains are active: a closed suction reservoir pulls fluid out regardless of position.
• A bandage over the drain is mandatory: it protects from contamination and monitors output.
• Most drains stay in 2 to 5 days and are removed when daily output drops below threshold.
• Never try to remove a drain at home: removal without veterinary assessment risks seroma reformation.

When drains are placed

Not every surgery requires a drain. Drains are indicated when:

• Dead space is too large to close by suturing: after large tumor removal, intermuscular lipoma excision, or extensive tissue dissection
• Significant post-operative fluid production is expected: hematoma-prone wounds, contaminated wounds with exudate
• Infection is already present: drainage of infected tissue and pus is part of treatment
• Walking sutures cannot fully bridge the space: particularly in obese dogs or after mastectomy

University of Illinois College of Veterinary Medicine confirms: "Drains are used commonly in small animal patients to address dead space, remove contaminated fluid, and improve tissue layer adherence."

Clinician's Brief (2017) documented a key outcome: "In a study evaluating drain placement after intermuscular lipoma removal, 0 of 5 dogs with a Penrose drain developed a seroma, whereas 4 of 6 without Penrose drain placement developed a seroma."

For how drains fit within the broader dead space management strategy, see drain placement as a dead space strategy.

Drain types: passive vs active

Penrose drain (passive)

The most common drain in small animal veterinary surgery. A soft, flat silicone or latex tube placed in the wound bed.

How it works:

• Fluid exits along the outer surface of the drain (not through it do not fenestrate a Penrose drain)
• Driven by gravity, capillary action along the drain surface, and pressure differential between wound bed and outside
• Must exit through a stab incision at the most gravity-dependent part of the wound

University of Illinois states: "To place the drain, create a small exit hole in the most gravity-dependent part of the wound bed, several centimeters away from the wound edge."

Properties:

• Simple, inexpensive, effective for superficial to medium-depth wounds
• Requires dependent positioning to function placement in a non-dependent location reduces effectiveness
• Open system: some risk of ascending bacterial contamination from the drain exit site

Penrose drain sizes range from 1/4 inch to 1 inch width. Fluid flows along the outer surface, so wider is better for high-output wounds.

Jackson-Pratt drain (active, closed suction)

A fenestrated silicone tube connected to a closed compressible reservoir (the "grenade").

How it works:

• The grenade is compressed, then sealed creating negative pressure that actively pulls fluid through the fenestrated tube end into the reservoir
• Does not depend on gravity can exit anywhere on the body
• Fluid is collected inside the closed reservoir, reducing contamination risk

Today's Veterinary Practice notes the benefits of active over passive: "Closed active drains use suction to actively remove exudate and close down dead space, can exit in a nondependent location, collect exudate in a closed system, and allow easy quantitative and qualitative assessment."

When Jackson-Pratt is preferred over Penrose:

• Deep wounds or wounds in non-dependent positions (dorsal body wall, thorax, joints)
• High-output wounds requiring quantitative monitoring
• High-infection-risk environments where the closed system reduces ascending contamination

For how closure is constructed around the drain exit site, see how to close around surgical drains.

How drain placement changes the closure strategy

When a drain is placed, the wound closure changes in two ways:

1. The drain exit is a second, separate opening a small stab incision placed 2 to 3 cm from the wound edge, always at the gravity-dependent aspect of the wound for Penrose drains.

2. The main incision is still closed fully the drain does not replace wound closure; it supplements it. The wound is closed in layers above the drain, with the drain entering the dead space from below and exiting laterally.

The drain is secured at the exit site with a single suture (often a Chinese finger trap or purse-string pattern) to prevent premature removal.

Owner care for a draining wound

Bandage: always on

A bandage over the drain exit site is mandatory at all times. It:

• Absorbs drain output and allows monitoring
• Prevents the dog from licking or pulling the drain
• Protects the drain exit from environmental contamination

For Penrose drains: DVM360 notes that passive drains "must be covered at all times."

Bandage change frequency

Change the bandage when it becomes wet through (strike-through) or at a minimum every 24 hours. Use clean technique: wash hands before, do not touch the inner surfaces of the new bandage.

Monitoring drain output

Watch for:

• Volume: should decrease daily as wound healing progresses
• Color: light red/pink early transitioning to straw-colored (normal); yellow or green (possible infection)
• Odor: minimal is acceptable; foul odor warrants same-day vet contact

For Penrose drains: a small amount of fluid on the bandage is expected. Soaking through within hours is a sign of high output that your vet needs to know about.

When to contact your vet

• Drain falls out before scheduled removal
• Wound around drain exit becomes red, swollen, or painful
• Output suddenly increases or becomes purulent
• Dog develops fever or lethargy alongside drain concerns

For post-operative monitoring of closures that include drains, see monitoring drains after closure.

Drain removal

Most drains are removed in 2 to 5 days. The criteria:

• Daily output has dropped to minimal levels (usually below 0.5 mL/kg/day as a rough guide)
• Discharge has transitioned from red/pink to clear or light straw color
• No signs of infection at the drain site

Drain removal is performed at the veterinary clinic. It does not typically require sedation in cooperative dogs. The securing suture is cut, and the drain is gently withdrawn in one smooth movement.

For the seroma prevention role of drains before and after removal, see drains to prevent seroma.

Frequently asked questions

Can my dog go outside with a drain in?

Yes, for leash walks on dry surfaces. Keep the drain and bandage clean and dry. Avoid puddles, wet grass, and any surface that could contaminate the drain exit. Do not allow the dog to swim or be bathed while a drain is present.

My dog pulled the drain out at home. What should I do?

Contact your vet the same day. If the drain was removed early, the dead space it was managing may still be producing fluid. Your vet will assess whether a seroma has started forming and whether a new drain is needed or whether pressure bandaging and activity restriction can manage the space going forward.

Does having a drain mean the surgery had a complication?

Not at all. Drain placement is a planned, proactive step in many procedures, particularly after large tumor removal or in obese patients. It reflects good surgical planning, not a problem during surgery.

A drain is a controlled, deliberate alternative to expecting sutures to manage a wound beyond their capability. When placed appropriately, monitored carefully, and removed at the right time, drains prevent the fluid accumulation that leads to seroma, infection, and wound breakdown. They require active owner involvement but are highly effective when that involvement is consistent.

Resources

• University of Illinois College of Veterinary Medicine. Use of Drains in Small Animal Patients. vetmed.illinois.edu
• Clinician's Brief. Wound Drain Placement: Step-by-Step Veterinary Guide. cliniciansbrief.com
• Clinician's Brief. Surgical Drains for Wound Management in Veterinary Medicine. cliniciansbrief.com
• Today's Veterinary Practice. Placement and Management: Jackson-Pratt Closed Active Suction Drain. todaysveterinarypractice.com