Not every wound should be closed immediately. When bacteria are already present in significant numbers, when tissue viability is uncertain, or when contamination cannot be fully cleared at the first visit, closing the wound traps the problem inside.

Delayed primary closure is the planned alternative. The wound is left open, cleaned and bandaged for a defined period, then closed surgically once the wound bed is healthy enough to support suture healing.

Quick answer: Delayed primary closure means closing a wound 3 to 5 days after injury, after open management has reduced bacterial counts and confirmed tissue viability, but before granulation tissue forms. It is used for contaminated wounds that cannot be safely closed at first presentation. The wound is cleaned with daily bandage changes, then closed surgically with standard suture techniques. It produces significantly lower infection rates than immediate closure of contaminated wounds.

Key takeaways

• Delayed primary closure occurs 3 to 5 days after injury, before granulation tissue forms.
• Used for contaminated wounds where immediate closure would trap bacteria.
• Daily wound care is required during the open phase: debridement, lavage, and bandage changes.
• Closure is performed surgically with standard suturing once the wound bed is healthy.
• Wounds closed after 5 days (once granulation tissue forms) are classified as secondary closure, not delayed primary.
• Second intention healing (leaving the wound to close on its own) is different from both no surgical closure is performed.

The four closure options: where delayed primary fits

Veterian Key (Open Wounds chapter) defines four strategies:

Today's Veterinary Practice (Wound Care Principles): "Third intention describes tertiary wound healing or delayed primary closure; it is best for infected or unhealthy wounds that are too contaminated for primary closure, but appear clean and well vascularized after approximately 2 to 5 days."

Wounds appropriate for delayed primary closure

Delayed primary closure is indicated when:

• Wound is 6 to 24 hours old with moderate contamination (too old or dirty for immediate primary closure)
• Bite wounds (animal bites are considered contaminated regardless of appearance see closing bite wounds for species-specific details)
• Traumatic wounds from road accidents, punctures, or foreign body penetration
• Moderately contaminated surgical wounds where complete debridement could not be achieved at first presentation
• Wounds with borderline tissue viability where it is unclear at first presentation which tissue will remain viable

Today's Veterinary Practice: "Wounds that fit in this category are: mildly contaminated wounds that require some debridement and those initially treated by open wound management for a short period of time."

The key qualification: the wound must be manageable within 3 to 5 days. If contamination is too severe or tissue necrosis is extensive, delayed primary closure is not achievable and secondary closure is used instead.

For how contaminated wound management determines whether delayed primary or alternative closure is needed, see contaminated wounds that require delayed closure.

The open wound management phase (days 1 to 5)

Day 1: initial wound assessment and debridement

• Sedate or anesthetize the patient
• Clip hair widely around the wound
• Lavage copiously with sterile saline under pressure to remove gross contamination
• Debride devitalized tissue (scalpel, scissors, or wet-to-dry dressings)
• Assess which tissue is viable and which requires further management

Merck Veterinary Manual: "The time between initial debridement and final closure varies according to the extent of contamination or infection. Minimally contaminated wounds may be closed after 24 to 72 hours. Longer periods may be required for heavily infected wounds."

Days 1 to 5: open wound care

• Bandage changes: daily, or more frequently if the bandage becomes soaked
• Wound lavage: each bandage change includes gentle lavage
• Debridement technique: wet-to-dry dressings remove necrotic tissue mechanically when pulled off; sugar or honey dressings draw fluid and provide antibacterial properties
• Assessment: each bandage change assesses whether the wound is ready for closure or needs continued open management

Veterinary Surgery Online: "Wounds are treated open for a few days with regular lavage, debridement (e.g. sugar, honey, wet-to-dry) and bandage changes to clean them in preparation for closure."

Ready for closure: what "healthy enough" looks like

• No visible purulent discharge
• Healthy granulation tissue beginning but not fully formed (healthy pink-red surface, not yellow or grey)
• Wound edges viable no necrotic margins
• Dog systemically well (no fever, normal appetite)
• Bacterial culture (if performed) shows reduced count

University of Minnesota (Clinical Skills Compendium): Secondary closure applies when delayed primary closure was "not sufficient enough due to persistent inflammation or infection" or "persistence of necrotic tissue that required serial debridement past 5 days."

The surgical closure at day 3 to 5

When the wound bed is ready, closure follows the same principles as any surgical wound:

1. Debride wound edges: fresh edges improve healing; remove any epithelium that has begun forming along the wound margins
2. Lavage: one final irrigation before closure
3. Evaluate for dead space: place drains if needed
4. Close in layers: subcutaneous layer, then skin
5. Suture material: monofilament absorbable for internal layers; monofilament non-absorbable or absorbable for skin

Note: the wound at this stage is typically less amenable to primary tension-free closure than a fresh wound the edges may have retracted, and tension-relieving patterns may be needed.

For how infection risk reduction is achieved through delayed closure compared to immediate closure of dirty wounds, see infection risk reduction through delayed closure.

Delayed primary closure in emergency contexts

In emergency surgery (GI obstruction, hemoabdomen, uroabdomen), the closure decision is complicated by patient instability and abdominal contamination.

For severely contaminated abdominal cases (fecal peritonitis, bile peritonitis), the abdomen may be left partially open (open abdominal management) for repeated lavage and re-exploration before delayed closure is performed.

For how closure decisions adapt in emergency surgical contexts, see delayed closure in emergency surgery contexts.

Second intention healing vs. delayed primary closure

These are often confused but are fundamentally different:

Delayed primary closure:

• Wound is cleaned and bandaged open for 3 to 5 days
• Surgical closure is performed once wound bed is healthy
• No granulation tissue at time of closure

Second intention healing:

• No surgical closure is performed
• The wound heals on its own by granulation, contraction, and epithelialization
• Used when closure is impossible or not indicated

For the full framework covering how delayed closure fits within wound closure principles, see delayed closure within wound closure principles.

Frequently asked questions

My dog has an open wound with daily bandage changes. When will it be closed?

Your vet is monitoring the wound through each bandage change. Closure is performed when the wound looks healthy no purulent discharge, viable tissue margins, and the wound bed is pink and moist. That typically occurs at day 3 to 5 in uncomplicated cases. More severe contamination may extend this timeline.

Will delayed closure heal as well as immediate closure?

Yes, when the conditions warrant it. Delayed primary closure applied appropriately produces equivalent or better healing outcomes than immediate closure of contaminated wounds. The additional healing time allows bacterial counts to drop to levels the wound can manage.

My dog's wound was left open after surgery. Is that a complication?

Not necessarily. In contaminated wounds, intentional open management is the correct choice. It is a planned step, not a failure of closure. The goal is to clean the wound bed adequately before surgical closure a process that produces better outcomes than forcing premature closure over a contaminated field.

Delayed primary closure is patience applied surgically. The 3-to-5-day window exists because bacterial counts in contaminated wounds fall to manageable levels in that timeframe when the wound is properly managed. Closing too early traps the problem; closing too late allows granulation tissue to form and changes the surgical approach entirely. The window is specific, and the daily wound management within it is what makes delayed closure succeed.

Resources

• Veterian Key. Open Wounds. veteriankey.com
• Veterinary Surgery Online. Wound Closure. vetsurgeryonline.com
• Merck Veterinary Manual. Initial Wound Management in Small Animals. merckvetmanual.com
• Today's Veterinary Practice. Basic Principles of Wound Care and Bandaging Techniques. todaysveterinarypractice.com

What happens at home in the two weeks after surgery determines as much about healing outcomes as what happened in the operating room. The wound that closes perfectly can still fail through licking, jumping, or unrecognized infection.

Owners who know what to check, how often, and what each finding means are far more likely to catch complications early when they are still manageable.

Quick answer: Check the surgical wound twice daily for the first 10 to 14 days. Normal findings: mild swelling and redness for 2 to 3 days, a thin dry crust at the wound margins, gradual improvement day by day. Abnormal findings requiring same-day contact: yellow or green discharge, foul odor, worsening redness beyond the wound margin, increasing swelling after day 3 to 4, wound opening (dehiscence), or any tissue protruding from the wound. Licking is the most preventable cause of post-operative closure failure.

Key takeaways

• Twice-daily wound checks for the full 10 to 14 days are the monitoring standard.
• Normal post-operative swelling and redness peaks at days 2 to 3, then progressively decreases.
• Seroma (soft fluctuant swelling) differs from infection and is usually harmless.
• Dehiscence (wound opening) is a same-day emergency cover with a clean cloth and call immediately.
• Licking is the most common owner-controllable cause of suture failure E-collar compliance is not optional.
• Pale gums, open wound with tissue protruding, or collapse require immediate emergency care.

What to check at each monitoring session

Twice-daily monitoring takes less than two minutes. The same checks, performed consistently, provide the trend data needed to distinguish normal healing from early complication.

Five things to assess at each check:

1. Wound edges: closed and apposed at all points? No visible gaps between suture sites?
2. Swelling: decreasing compared to the last check? Or increasing?
3. Color: pink and normalizing? Or reddening, darkening, or developing pale areas?
4. Discharge: none, or only a small amount of dried serous crust at the wound margins?
5. Odor: none, or any smell from the wound area?

Metropolitan Veterinary Associates: "The incision should be monitored for redness, swelling, oozing, heat or pain to the touch. Any of these signs may indicate an incisional infection."

Normal findings by timeline

Days 1 to 2

• Mild swelling around the incision: normal the body's inflammatory response is at its peak
• Mild redness at the wound margins: normal
• Small amount of dried bloody crust at suture sites: normal
• Pet may be quiet, less active than usual: normal effect of anesthesia and post-operative pain management

MedVet: "It is normal to see mild lethargy, reduced appetite, or slight discomfort during the first 24 to 72 hours."

Days 3 to 5

• Swelling should begin to decrease from its peak
• Redness should be stabilizing or reducing not spreading
• A small firm ridge along the wound line is normal: this is early collagen deposition
• Pet appetite should be returning toward normal

Days 5 to 10

• Progressive improvement day by day
• The wound surface should look drier, flatter, and less reactive
• Sutures remain intact and wound edges remain fully apposed

Days 10 to 14

• Wound should be fully closed, dry, and healed at the surface
• Suture removal recheck visit (for external sutures)
• Vet assesses wound before removing sutures removal may be deferred if healing is incomplete

For how suture removal timing is assessed at the recheck in dogs, see suture removal timing at the day 10-14 recheck. For cats, see suture removal timing at the feline recheck.

Distinguishing seroma from infection

Both seroma and infection produce swelling near the surgical site. They require different responses.

Liberty Animal Hospital: "Seroma: fluid accumulation at the incision site due to tissue irritation this is normal. Continue with cold compress only until the swelling has gone down. The body will absorb it over time."

If you cannot confidently distinguish a seroma from an early infection, contact your vet. Assessment may require palpation or aspiration to determine fluid character.

For how seromas are prevented at the closure stage, see seroma prevention during closure.

Dehiscence: when the wound opens

Wound dehiscence is the partial or complete opening of a sutured wound. It is a same-day emergency not a wait-and-see situation.

PetPlace: "When sutures break down, the underlying tissues have the potential to protrude through the incision and be exposed to the exterior. This can lead to serious infections, which may be fatal."

What to do if the wound opens:

1. Apply a clean towel or cloth gently over the wound
2. Do not attempt to replace protruding tissue
3. Do not apply ointments, disinfectants, or saline without vet guidance
4. Transport to the vet or emergency clinic immediately

Common causes of dehiscence:

• Licking or chewing the sutures
• Jumping, running, or abrupt activity
• Sutures removed too early
• Infection undermining the closure from within
• Underlying tension that was not adequately managed at surgery

For how common closure errors produce dehiscence, see closure errors that lead to dehiscence.

Infection: what to look for

Early surgical site infection typically presents between days 3 and 7. The signs progress from mild to severe as the infection establishes.

Early signs (days 3 to 5):

• Redness extending beyond the immediate wound margin
• Increased warmth at the wound site
• Mild increase in discharge (serous becoming slightly cloudy)

Established infection (days 5 to 10):

• Purulent discharge (yellow, green, or brown)
• Foul odor
• Wound swelling increasing rather than decreasing
• Pet showing systemic signs: lethargy, reduced appetite, fever

Contact your vet the same day if you notice any of the early signs. Do not wait for the established infection stage early treatment is significantly simpler than treating an established surgical site infection.

Activity restriction: enforcing it at home

Metropolitan Veterinary: "Dogs and cats should be kept from jumping up/down on/from high surfaces, running up steps or any other activity that puts tension on the incision. Excess tension can lead to dehiscence."

Practical activity restriction strategies:

• Dogs: leash-only outdoor activity for 10 to 14 days; confine to one room or use a pen when unsupervised
• Cats: confine to a room without high furniture; prevent stair access
• Both: separate from other pets who may play with or groom the wound

The challenge is that pets often feel better before the wound has adequate tensile strength. A dog that seems completely normal at day 5 does not have a day-5 wound the tissue is still in the active repair phase and cannot tolerate the same forces the dog is willing to exert.

E-collar compliance: non-negotiable

Licking introduces oral bacteria directly to the wound surface, mechanically disrupts suture lines, and can remove external sutures within minutes of unsupervised access.

MedVet: "To prevent licking, which can delay healing, cause infection, or lead to the incision opening, use an Elizabethan collar (cone), a cervical collar, or cover the incision with a T-shirt or bandage."

The E-collar must be worn:

• At all times, including during sleep
• When the owner is in the room but not actively watching the pet
• When the pet is in its crate or confined space

Alternatives to the standard E-collar if compliance is difficult: inflatable donut collar (cats often tolerate better), surgical recovery suit, or soft fabric cone.

Emergency signs: call immediately

Some findings do not wait for a scheduled call to the vet. Seek care immediately for:

• Pale or white gums: indicates blood loss or cardiovascular compromise
• Blue-tinged gums or rapid breathing: respiratory distress
• Wound fully open with tissue protruding: cover and transport immediately
• Collapse or inability to stand
• Bright red active bleeding that does not stop within 5 minutes of gentle pressure

MedVet: "Pale gums, which can indicate potential blood loss or poor circulation seek veterinary care immediately, regardless of the time of day."

For the full closure checklist that precedes this monitoring period, see closure checklist prior to discharge. For how drain monitoring integrates with wound monitoring, see monitoring wounds with drains in place.

Frequently asked questions

My dog's wound looks fine but she keeps trying to lick it. Should I be worried?

The licking attempt is the warning sign the wound does not need to look damaged yet for the E-collar to be essential. Licking can remove sutures or disrupt healing within minutes. The fact that she is attempting to lick means the E-collar must be worn consistently, not just when she actively succeeds. Wounds that look fine often look that way because the E-collar has been working.

There is a small bump near the wound that appeared on day 4. How do I know if it is a seroma or infection?

Gently palpate (press softly) the bump. A seroma feels soft and fluid-filled, like a water balloon under the skin. An early infection usually feels firmer, is warmer to the touch, and the pet shows some discomfort when you touch it. If the bump is soft and the pet is otherwise well and eating, a seroma is more likely. Either way, contact your vet at the next business opportunity and immediately if the bump is warm, the pet seems unwell, or discharge is present.

My cat won't eat after surgery. Is that a complication?

Reduced appetite for 24 to 72 hours is common and expected. Cats that refuse to eat for more than 72 hours after surgery require prompt veterinary assessment. Metropolitan Veterinary: "Cats, in particular, cannot tolerate anorexia for long periods. They are predisposed to developing severe liver disease (hepatic lipidosis/fatty liver) within days of complete anorexia."

Post-operative monitoring is owner-controlled quality control for the surgeon's work. The wound that closes well can still fail but usually only if something external disrupts it. Every day of consistent monitoring, E-collar compliance, and activity restriction protects the closure that was placed and gives it the environment it needs to heal.

Resources

• Metropolitan Veterinary Associates. Abdominal Surgery: Post-Operative and Incisional Care. metro-vet.com
• MedVet. Caring for Your Cat or Dog After Surgery. medvet.com
• PetPlace. Postoperative Complications in Dogs. petplace.com
• Liberty Animal Hospital. Post-Surgery Guidelines. libertyanimalhospital.com

TPLO surgery creates one of the most mechanically demanding wound closure environments in small animal surgery. The incision is placed over a joint that the dog begins loading within days. The underlying repair involves bone cutting and plate fixation. And the patient is often a large, active dog whose energy level returns faster than the tissues heal.

Getting the closure right every layer, the right material, the right tension is what keeps the infection risk low and the repair protected through the critical 8 to 12 week healing period.

Quick answer: TPLO closure proceeds in four layers: (1) joint capsule PDS 0 to 2-0, simple continuous or interrupted pattern to restore synovial seal; (2) deep fascia / muscle fascia PDS 0 to 2-0, continuous or interrupted; (3) subcutaneous tissue Monocryl or Vicryl 2-0 to 3-0, simple continuous; (4) skin interrupted nylon 3-0 to 4-0 or staples (staples are widely used for TPLO skin closure for speed). External sutures or staples are removed at 10 to 14 days. Activity restriction continues for 8 to 12 weeks regardless of wound appearance.

Key takeaways

• Joint capsule closure is the most critical TPLO layer: restores synovial seal and protects the implant.
• PDS 0 to 2-0 is standard for joint capsule and fascial closure; long retention matches healing timeline.
• Staples are commonly used for TPLO skin closure because they are fast to place and tolerate some movement.
• The underlying plate and bone are permanent implants infection at the closure site can reach them, making aseptic technique non-negotiable.
• Activity restriction through 8 to 12 weeks protects both the closure and the osteotomy healing regardless of wound appearance.
• Infection risk at TPLO sites is higher due to implant presence; monofilament in all buried layers is essential.

Why TPLO closure differs from standard orthopedic incisions

TPLO creates a unique closure environment because of what lies directly beneath the incision:

• A stainless steel or titanium plate with multiple screws, fixed to the tibia
• A tibial osteotomy site (bone cut) healing under controlled load
• The lateral joint capsule opened for surgical access
• Implants that cannot mount an immune response if bacteria reach them

Any closure failure whether from suture material choice, inadequate dead space elimination, or post-operative licking creates a direct pathway toward implant-associated infection. This is a significantly more serious consequence than infection after a routine spay or skin mass removal.

For the general principles of orthopedic incision closure that apply here, see orthopedic incision closure principles.

Layer 1: Joint capsule

Why this layer matters most

The joint capsule closure restores the synovial seal. Failure here allows:

• Synovial fluid leakage into the subcutaneous tissue
• External bacteria to access the joint space and implant surface
• Loss of the pressure environment that supports bone healing

Technique and material

Pattern: simple continuous or interrupted, based on capsule length and tissue quality.

Material: PDS (polydioxanone) 0 to 2-0 on a taper-point needle

• PDS retains approximately 70% of tensile strength at 2 weeks and 50% at 4 to 6 weeks
• Monofilament surface: minimal bacterial adhesion
• Absorbed over 180 to 210 days long after joint capsule healing is complete

Bite technique: full-thickness bites through the capsule wall, ensuring every bite incorporates the fibrous capsule layer. Partial-thickness bites fail under joint motion.

What not to use: braided absorbable sutures (Vicryl) in this layer the braided structure wicks bacteria from the joint environment along the suture strand, creating a direct infection pathway to the implant.

Layer 2: Deep fascia and muscle fascia

After joint capsule closure, the deep fascial layers overlying the surgical field are closed.

Pattern: simple continuous or interrupted absorbable

Material: PDS 0 to 2-0, sized to patient

Key principle: the fascial layer must be engaged in each bite not just the muscle belly. Muscle tissue is not load-bearing in this context and tears through under the repetitive mechanical load of the dog's movement.

Dead space: the space created by elevating the muscle and retracting the patellar tendon must be managed at this layer. Inadequate closure here leads to hematoma or seroma formation directly over the implant.

For how the fascial layer closure relates to infection risk in orthopedic cases, see infection risk in orthopedic closure.

Layer 3: Subcutaneous tissue

Pattern: simple continuous absorbable

Material: Monocryl 2-0 to 3-0, or Vicryl 2-0 to 3-0

Purpose: eliminate dead space between the deep closure and the skin. In large breed dogs with significant subcutaneous fat, this layer requires careful attention inadequately closed dead space over a TPLO plate creates a seroma risk that can progress to implant contamination.

Drain consideration: if significant dead space cannot be eliminated by suturing common after TPLO in obese patients drain placement is indicated. The drain exits through a stab incision separate from the primary wound.

For the full post-operative monitoring checklist that begins from this closure, see post-operative monitoring after TPLO closure.

Layer 4: Skin closure

Why staples are common for TPLO skin closure

Staples are placed in 2 to 3 seconds each, compared to 15 to 30 seconds per interrupted suture. For a 10 to 15 cm TPLO incision, this difference is clinically meaningful reducing anesthesia time in a procedure that is already longer than routine soft tissue surgery.

Published research (PMC9913468) confirms equivalent healing outcomes between staples and interrupted external sutures in dogs. Staples require a specific removal tool at the 10 to 14 day recheck.

The one specific TPLO caution: MSPCA-Angell notes that staples are prone to deforming and opening under sustained high tension. For TPLO closures where significant wound tension exists (large, heavily muscled dogs), interrupted sutures or tension-relieving patterns may be more appropriate.

Intradermal closure as an alternative

For TPLO patients where E-collar compliance is uncertain or the owner preference is for no removal visit, 4-0 Monocryl intradermal closure is appropriate. Published data (JAVMA 2026, 96 TPLO patients) specifically confirms that taper-point needles are non-inferior to reverse cutting needles for intradermal TPLO skin closure.

Suture size guide by patient

For the suture size selection framework that underpins these choices, see suture size selection for orthopedic cases.

Post-operative monitoring after TPLO closure

The TPLO closure is subject to the same monitoring principles as any orthopedic closure but with higher stakes because of the implant below.

Twice-daily checks for 14 days:

• Wound edges apposed; no gaps
• Swelling decreasing from peak (days 2 to 4) increasing swelling after day 5 is a concern
• No discharge, or only a small amount of serous crust at suture sites
• No odor

Suture/staple removal: day 10 to 14 at the post-operative recheck.

Activity restriction continues regardless of wound healing: the wound surface may look healed at 2 weeks, but the osteotomy site and the joint capsule are still in the early repair phase. Activity restriction (leash walks only, no running or jumping) continues for 8 to 12 weeks.

For the full closure protocol checklist applicable to TPLO, see closure checklist for TPLO procedures.

Frequently asked questions

My dog had TPLO and the vet used staples on the skin. Is that standard?

Yes. Staples are widely used for TPLO skin closure because they are fast to place, handle movement well, and produce equivalent cosmetic outcomes to external sutures in published veterinary research. The staple remover visit at day 10 to 14 is a brief, low-stress procedure.

The skin around my dog's TPLO site looks healed at day 10. Can activity restriction end now?

No. Surface healing does not indicate complete repair at any layer below the skin. At day 10, the joint capsule is in the early repair phase, the fascial layers are at 30 to 50% of original tensile strength, and the tibial osteotomy is still consolidating. Activity restriction continues for 8 to 12 weeks from surgery the wound appearance at day 10 is not the relevant endpoint.

What are signs of infection at a TPLO site that require urgent care?

Early: increasing redness or warmth beyond the wound margin, excessive swelling appearing after day 4 to 5, any purulent discharge. These require same-day veterinary contact. Later signs: fever, lethargy, inappetence combined with wound changes these may indicate implant-associated infection and require immediate assessment. Do not wait for the scheduled recheck if these signs appear.

TPLO closure carries high stakes because the implant beneath the wound is unforgiving of infection. Every closure decision monofilament in buried layers, adequate dead space elimination, correct skin closure method, strict activity restriction is made to protect both the wound and the surgical repair it covers. A closure that holds for 10 days is not enough; it must hold for 12 weeks.

Resources

• Clinician's Brief. How to Fine-Tune Suture Choices for Today's Veterinarian. cliniciansbrief.com
• JAVMA 2026 (Kieves et al.). Taper Suture Needles Are Noninferior to Reverse Cutting Needles for Intradermal Skin Closures in TPLO. avmajournals.avma.org
• PMC9913468 (University of Thessaly). Evaluation of Incisional Wound Healing in Dogs after Closure with Staples or Tissue Glue vs. Intradermal Suture. ncbi.nlm.nih.gov
• VCA Animal Hospitals. Care of Surgical Incisions in Dogs. vcahospitals.com

Emergency surgery closure is not simply faster elective surgery closure. The patient's physiological state coagulopathy, hypothermia, acidosis, hemodynamic instability shapes every closure decision in ways that have no equivalent in a planned, stable procedure.

The core principle is this: do what is necessary to keep the patient alive, defer everything else to a second surgery when the patient can tolerate it.

Quick answer: Emergency abdominal surgery closure follows a spectrum: standard layered closure when the patient is stable enough to tolerate it; damage control surgery (abbreviated technique prioritizing hemorrhage control and contamination reduction, temporary closure, definitive repair 24 to 48 hours later) when the patient is hemodynamically unstable. MSPCA-Angell: "Phase 2 is the first surgery where the primary goal is to limit severe hemorrhage and control bowel leakage. No attempt is made to reconnect discontinuous sections of bowel that would be done at the second definitive surgery."

Key takeaways

• Damage control surgery (DCS) prioritizes hemorrhage control and contamination reduction over complete anatomical repair.
• Temporary abdominal closure is used when definitive closure cannot be safely performed in an unstable patient.
• Definitive surgery follows 24 to 48 hours later, once the patient is hemodynamically stable.
• Contaminated wounds from GI spillage, uroabdomen, or bite wounds require delayed primary closure principles even in emergency contexts.
• Continuous suture patterns are used in damage control to minimize time while achieving adequate contamination control.
• Standard layered closure is used when the emergency patient is sufficiently stable to tolerate full anesthetic time.

The stability spectrum: how it determines closure

Hemodynamically stable emergency patient

Some emergency patients a GI foreign body obstruction without perforation, a splenic mass removed before rupture, a planned exploratory for a suspected obstruction arrive in or can be stabilized to a state that allows complete anatomical repair.

For these patients, standard layered closure proceeds:

• Hollow organ closure with inverting patterns (Cushing, Lembert) if enterotomy was performed
• Abdominal wall closure with PDS or equivalent in simple continuous
• Subcutaneous closure with Monocryl or Vicryl
• Skin closure with interrupted nylon or intradermal Monocryl

These closures follow the same protocol as equivalent elective procedures. The emergency designation describes the urgency of the decision to operate, not necessarily a modification of technique.

Hemodynamically unstable emergency patient

The lethal triad of trauma acidosis, coagulopathy, and hypothermia creates a physiological state incompatible with prolonged surgery. Every additional minute under anesthesia risks coagulation failure, cardiac arrest, or irreversible multi-organ injury.

MSD Veterinary Manual: "Damage control surgery is a limited laparotomy designed only to control hemorrhage and/or to minimize contamination but not to perform definitive surgical repair, to avoid similar clinical complications. Definitive care is delayed until the patient is able to tolerate extended anesthesia and surgery."

Damage control surgery: the three-phase approach

MSPCA-Angell (Damage Control Surgery: Is There a Role in Veterinary Medicine?):

Phase 1: Pre-operative stabilization

• Limit hemorrhage
• Manage hypothermia
• Transfuse blood products to correct coagulopathy
• Get the patient to the operating room as quickly as safely possible

Phase 2: Damage control laparotomy

• Control hemorrhage (pack the abdomen with laparotomy pads, ligate major bleeding vessels)
• Reduce contamination (rapid running suture closure of identified bowel leaks; do not attempt full anastomosis)
• "Identified lesions are rapidly sutured in running/continuous suture pattern to reduce contamination"
• Urinary diversion if bladder or urinary tract rupture is present (urinary catheter, Jackson-Pratt drain)
• Temporary abdominal closure leave laparotomy pads in place for compression if needed
• Do not attempt bowel reconnection

Phase 3: Definitive surgery (24 to 48 hours later)

• Re-enter the abdomen once the patient has achieved hemodynamic stability
• Perform complete anatomical repair (bowel anastomosis, permanent organ repair)
• Definitive abdominal wall closure

VetEducation: "Definitive surgical repair should take place following patient stabilisation, and usually occurs 24 to 48 hours following damage control surgery."

For how the delayed primary closure principles apply after damage control, see delayed closure in emergency context.

Temporary abdominal closure

When the abdomen must be left open between damage control and definitive surgery, a temporary closure barrier is applied.

Purpose: prevent evisceration, limit contamination, allow abdominal decompression if needed.

Technique: a sterile barrier (damp laparotomy pads, sterile plastic sheeting, or negative-pressure dressing) is placed over the abdominal contents, then the skin is loosely approximated with large interrupted sutures or towel clamps. This is not a wound closure it is a controlled open abdomen.

MSPCA-Angell: "The abdomen is then left open with a temporary closure or barrier to limit contamination."

GI contamination: closure decisions after bowel leakage

Bowel spillage into the abdominal cavity creates a contaminated environment. Closure decisions must account for this regardless of whether the procedure is elective or emergency.

Intraoperative spillage during elective surgery: lavage the abdomen thoroughly, consider drain placement, proceed with standard closure. The contamination was controlled during the procedure.

Pre-existing peritonitis (e.g., GI perforation before surgery): the contamination is established. After bowel repair or resection, abdominal lavage is performed (warm saline), a drain is placed (Jackson-Pratt or closed suction), and the abdomen is closed over the drain. In severe cases of septic peritonitis, open abdominal management may be preferred.

DVM360: "Drainage of the abdomen may be indicated in cases such as septic peritonitis and bile peritonitis. In cases of septic peritonitis in small animals, the mortality rate is 30 to 50%."

For how contamination principles shape the full closure decision in wound management, see contaminated wound closure principles.

Uroabdomen and bile peritonitis: specific closure considerations

Uroabdomen (bladder or urinary tract rupture):

• Surgical repair of the rupture site using a simple continuous absorbable suture
• Urinary catheter placement for bladder decompression post-repair
• Closed abdominal drain for residual urine or ongoing minor leakage
• Standard layered abdominal wall closure once the source is controlled

Bile peritonitis:

• Cholecystectomy or biliary repair depending on the source
• Copious abdominal lavage
• Closed abdominal drain
• Patients with bile peritonitis have significant systemic consequences (inflammation, coagulopathy) the closure decision must account for the patient's metabolic state

Skin and body wall closure in emergency surgery: practical considerations

Time under anesthesia: every additional layer of closure adds anesthetic time. In an unstable patient, subcutaneous closure may be simplified or omitted if it would extend surgery time dangerously.

Contaminated skin wounds (trauma cases): bite wounds, degloving injuries, and penetrating trauma present to emergency rooms as contaminated. Do not close these wounds primarily. Manage open with daily wound care and delayed primary closure at day 3 to 5.

For how common closure errors apply in emergency settings, see closure errors in emergency cases. For the wound closure principles that underpin emergency closure decisions, see principles of wound closure in emergency context.

What owners need to understand about emergency surgery recovery

Surgery may have been abbreviated: if your pet underwent damage control surgery, a second procedure is planned. The first surgery controlled the immediate life threat; the second surgery completes the anatomical repair.

Recovery timeline is less predictable: unlike elective surgery with known procedure scope, emergency cases may have ongoing fluid losses, infection risks, or metabolic instability that extend the recovery compared to a comparable elective procedure.

Drains: emergency cases more frequently require drains for abdominal or wound fluid management. These are typically removed within 3 to 7 days but will be assessed at each recheck.

For the post-operative monitoring that follows emergency closure, see post-op monitoring after emergency surgery closure.

Frequently asked questions

My dog had emergency abdominal surgery and the vet mentioned a possible second surgery. Does that mean something went wrong?

Not at all. In some cases, damage control surgery is the planned approach controlling the most critical problem (hemorrhage or GI contamination) while the patient is too unstable for complete repair. The second surgery is part of the protocol, not a complication. Your vet should have explained this plan.

The vet said they "closed the abdomen quickly." Does that mean the closure is inadequate?

Rapid closure in an emergency does not mean inadequate closure. A skilled surgeon can perform a sound abdominal wall closure quickly using continuous suture technique. "Quickly" refers to the overall surgical time being limited by the patient's stability, not to cutting corners on the structural closure.

My cat had emergency abdominal surgery and there is a drain coming from the wound. How long will it stay?

Drains after emergency abdominal surgery typically remain for 3 to 7 days, depending on output and the underlying condition. For septic peritonitis, drains may remain longer. Drain output is assessed at each recheck decreasing volume and clearer color (from bloody to clear serous) indicate the drain is ready for removal.

Emergency closure strategy is defined by one constraint: what can this patient safely tolerate right now? Standard layered closure when the patient is stable. Damage control when they are not. Temporary closure when even damage control cannot be completed safely. In every case, the goal is the same get the patient out of the operating room alive, then finish the repair when they can survive the finishing.

Resources

• MSPCA-Angell. Damage Control Surgery: Is There a Role in Veterinary Medicine? mspca.org
• VetEducation. Damage Control Surgery for Traumatic Haemoabdomen in Dogs and Cats. veteducation.com
• MSD Veterinary Manual. Trauma in Emergency Medicine in Small Animals. msdvetmanual.com
• DVM360. Drains: Proper Use and Management. dvm360.com

Every closure decision which material, which pattern, which timing can be traced back to a small set of principles that apply universally across tissue types, species, and procedures.

Understanding these principles is what separates wound closure from a protocol list. A surgeon who understands why a principle exists can adapt it correctly when the case does not fit the textbook exactly.

Quick answer: The core principles of wound closure in veterinary surgery are: (1) tissue apposition without inversion or eversion where it is not desired, (2) tension avoidance at wound edges, (3) dead space elimination, (4) aseptic technique throughout, (5) minimum suture material consistent with wound strength requirements, and (6) closure timing matched to wound contamination level. These principles apply at every layer and in every tissue type.

Key takeaways

• Tissue apposition means wound edges are brought into contact, not compressed, inverted, or everted (except where eversion is specifically indicated).
• Tension avoidance is achieved through layered closure, undermining, walking sutures, and tension-relieving patterns not by pulling skin edges harder.
• Dead space elimination prevents seroma formation, which creates the conditions for bacterial growth.
• Aseptic technique throughout the closure phase is as important as during the procedure itself.
• Minimum suture is the guiding size principle every suture is a foreign body and a potential nidus for bacteria.
• Closure timing determines whether immediate primary, delayed primary, or secondary closure is used.

Principle 1: Tissue apposition

Apposition means the wound edges are brought into contact touching, aligned, and at the same plane. It is not compression, not eversion (turning edges outward), and not inversion (turning edges inward), unless those specific outcomes are indicated.

Veterian Key (Primary Wound Closure, Fahie): "In primarily closed wounds with ideal apposition of subcutaneous tissues, the dermis, and the epidermis, healing may occur simply by reepithelialization at a rate of approximately 1 mm/day. A wound with perfect apposition may therefore have an epithelial seal within 24 hours."

What disrupts apposition:

• Sutures tied too tight: wound edges are compressed, not apposed blood supply is compromised
• Sutures too far apart: gaps remain between sutures where the edges are not touching
• Wound edges at different depths: one edge is deeper than the other, creating a step that cannot close by surface healing

Where eversion is specifically desired:

• Skin closure patterns that produce slight eversion (vertical mattress) help prevent the tendency of skin closures to invert, which would sink the wound surface below the surrounding skin and delay healing

Veterinary Surgery Online: "The arrangement that creates the least amount of tension and often the smallest dog ears is the one to pick."

For how apposition applies in each layer, see apposition in the layered closure context.

Principle 2: Tension avoidance

Tension at wound edges reduces blood flow. A suture that creates ischemia at the tissue-suture interface creates conditions for infection and necrosis the opposite of healing.

Today's Veterinary Practice (Wound Care Principles): "Wounds that are deemed healthy and can be closed without tension indicate primary closure."

Tension reduction strategies:

• Layered closure: closing deep layers first removes tension from the superficial skin closure
• Undermining: releasing skin from subcutaneous attachments to provide additional reach
• Walking sutures: advancing skin subcutaneously before placing skin closure sutures
• Tension-relieving patterns: horizontal mattress, vertical mattress, NFFN
• Releasing incisions: parallel cuts in adjacent skin to allow closure without tension
• Incision orientation: Veterinary Surgery Online: "Aim to close wounds along tension lines of skin where possible."

For how tension is managed when it cannot be eliminated, see tension-relieving techniques in wound closure.

Principle 3: Dead space elimination

Any gap remaining between tissue planes after closure fills with serum. Serum is protein-rich and warm an excellent bacterial growth medium. Seromas that become infected are far more serious than the wound they formed in.

DVM360 (Wound Management Basic Principles): "Primary closure should eliminate dead space and provide good anatomical apposition of tissue."

Dead space elimination strategies:

• Subcutaneous closure to approximate fat layers
• Walking sutures to tack skin to fascia
• Drain placement when suturing alone cannot eliminate the space

For how dead space connects to surgical drain placement decisions, see dead space elimination and drain use.

Principle 4: Aseptic technique

The surgical site is at maximum vulnerability during closure. All instruments, suture material, gloves, and draping that contact the wound during closure must be sterile.

DVM360: "Sterile gloves are required to manipulate the wound. Pain medication should be delivered appropriately to the animal."

Closure-phase asepsis risks:

• Glove contamination during the procedure (re-glove before closure if contamination is suspected)
• Suture material package contamination (inspect packaging before opening)
• Instrument contamination through contact with non-sterile surfaces

Infection transmission during closure:

• Braided suture materials wick bacteria along their strands monofilament is preferred in contaminated cases
• Each suture is a foreign body that reduces the local bacterial count needed to establish infection

For how suture material type affects infection risk at closure, see suture material infection risk at closure.

Principle 5: Minimum suture material

Every suture left in the body is a foreign body. It provokes a local inflammatory response. If it is braided, it provides shelter for bacteria. If it is non-absorbable, it remains as a permanent nidus unless removed.

DVM360 (Basic Principles of Wound Management): "The amount of suture should be maintained to a minimum because it can act as a nidus for bacteria. Monofilament absorbable sutures of a small size are recommended."

Practical application:

• Use the smallest suture size that provides adequate tensile strength for the tissue
• Use monofilament rather than braided in internal layers whenever possible
• Use absorbable rather than non-absorbable in all buried layers
• Avoid using a larger suture "for security" the additional foreign material outweighs the benefit

For how suture size selection implements this principle, see suture size selection to minimize foreign material.

Principle 6: Closure timing matched to wound condition

Not every wound should be closed immediately. The contamination level, wound age, tissue viability, and patient condition all determine whether immediate primary, delayed primary, or secondary closure is appropriate.

Veterinary Surgery Online: "If a wound is contaminated or dirty, primary closure should not be performed. It is best to perform daily bandaging until debridement is complete, then reassess and close if indicated."

For the full delayed primary and secondary closure decision process, see closure timing decisions in wound management.

How the principles interact

These principles do not operate in isolation. Each one depends on the others being met:

• Apposition without tension: you cannot achieve good apposition if tension is pulling the edges apart tension management precedes the final apposition step
• Dead space elimination while minimizing suture: more sutures close more dead space but add more foreign material the right number is the minimum that achieves elimination
• Asepsis protects all the others: contamination during closure can undermine perfect apposition, ideal dead space management, and correct suture selection simultaneously

Understanding the interactions is what allows a surgeon to make correct closure decisions in cases that do not fit a standard protocol.

For the surgical closure protocol checklist that applies these principles in sequence, see closure checklist implementing these principles.

Frequently asked questions

The vet said my dog's wound needs to "close without tension." What does that actually mean?

It means the wound edges can be approximated without pulling the surrounding skin under significant mechanical force. A wound that closes "under tension" has visible stretching of the skin, pale or blanching edges, and sutures that are clearly under load. A wound that closes without tension has the edges meeting with minimal force the skin comes together naturally rather than being pulled together.

If dead space is so dangerous, why doesn't the vet always put in a drain?

Drains have their own risks they create an entry pathway for bacteria and require management and a removal visit. The decision to use a drain is made when the dead space cannot be adequately managed by suturing alone, or when the expected fluid production is too great for sutures to control. For most routine procedures, appropriate subcutaneous closure is sufficient to eliminate dead space without a drain.

Can these principles be overridden in an emergency?

Some can be adapted under emergency conditions closure timing may be abbreviated, suture material choices may be based on what is available, aseptic technique may be difficult to maintain perfectly. The damage control principle applies: do what is necessary to manage the immediate threat, then revisit the other principles at definitive surgery. The principles are not abandoned; they are reprioritized.

These six principles are not a checklist they are a framework. Apposition, tension avoidance, dead space elimination, asepsis, minimum suture, and appropriate timing are the reasons behind every specific technique and material choice in surgical wound closure. Understanding the reasons allows the decisions to be made correctly even when the situation is unfamiliar.

Resources

• Veterian Key. Primary Wound Closure (Fahie). veteriankey.com
• DVM360. Basic Principles of Wound Management. dvm360.com
• Veterinary Surgery Online. Wound Closure Continued. vetsurgeryonline.com
• Today's Veterinary Practice. Principles of Wound Care and Bandaging Techniques. todaysveterinarypractice.com

Surgical drains are not a sign that something went wrong. They are a deliberate clinical decision a way of managing fluid that the body will inevitably produce in response to dead space, contamination, or tissue injury, before that fluid becomes a seroma, abscess, or infection.

The closure decisions made around a drain placement site are as important as the drain itself. Where the drain exits, how it is secured, and how the primary wound is closed relative to the drain all affect whether the drain works as intended.

Quick answer: Surgical drains exit through a separate stab incision at least 1 cm from the primary wound closure never through the primary incision itself, as this increases wound dehiscence risk. Passive Penrose drains are secured with 1 to 2 simple interrupted nonabsorbable sutures at the exit site. Active closed-suction drains (Jackson-Pratt) are secured with a purse-string suture at the exit and a Chinese finger-trap suture to prevent migration. The primary wound is closed normally in layers above and around the drain.

Key takeaways

• Drains exit through a separate stab incision, not through the primary wound this protects the primary closure from dehiscence.
• Passive Penrose drains are secured at the exit with 1 to 2 simple interrupted nonabsorbable sutures.
• Active Jackson-Pratt drains use a purse-string exit seal and Chinese finger-trap suture for secure fixation.
• The exit site is not sutured closed at removal it heals by second intention.
• Drains typically remain 2 to 7 days depending on output volume and color.
• Never fenestrate a Penrose drain this reduces surface area for capillary drainage and increases tearing risk at removal.

When drains are placed

Drains are placed when the surgeon cannot eliminate dead space through suturing alone, or when significant contamination or fluid production is expected post-closure.

Common indications:

• Large dead space after mass excision (tumor removal, extensive soft tissue dissection)
• Contaminated wounds where seroma infection risk is high
• Seroma or abscess drainage after established fluid pockets
• Abdominal drainage after peritonitis, bile peritonitis, or uroabdomen

For how dead space elimination through suturing reduces the need for drains, see dead space management and when drains are needed. For how proper drain placement prevents seroma formation, see seroma prevention with drain placement.

Passive vs. active drains

Passive drains (Penrose)

A flat latex tube that relies on gravity and capillary action to draw fluid from the wound to the external exit. Fluid seeps along the outer surface of the tube.

Properties:

• Works by gravity and capillary action must exit at the most dependent (lowest) part of the wound pocket
• Requires an open exit (not sealed) to function
• Simple, inexpensive, easily placed
• Higher risk of retrograde bacterial contamination than active drains keep the exit covered with a sterile bandage

DVM360: "Passive drains need to exit at the most dependent part of the wound or abscess pocket and must be covered at all times."

Active drains (Jackson-Pratt, closed-suction)

A perforated tube connected to a sealed collection reservoir that maintains gentle negative pressure, actively pulling fluid from the wound.

Properties:

• Works independently of gravity can be positioned in locations where passive drainage would fail
• Closed system lower bacterial contamination risk
• More expensive; requires a functional reservoir
• Better for high-volume drainage or wounds in areas of high movement (axilla, groin)

Clinician's Brief: "Active drains are secured with a purse-string suture to create a seal and a finger-trap suture to hold it in place."

Drain placement technique: where the exit goes

The drain exit site is not through the primary incision. It must be separate.

Clinician's Brief (Wound Drain Placement): "Exit the drain through a separate incision at least 1 cm from the primary suture line. Exiting drains through the primary incision line increases the risk for wound dehiscence."

DVM360 (Surgical Drains in Small Animal Wound Management): "It should not exit along the lines or within the plane of wound closure, as this may provide an entry point for bacteria or may result in dehiscence and additional drainage along the suture line."

Stab incision technique:

1. With the primary wound fully closed, the surgeon uses hemostatic forceps to tunnel subcutaneously from the wound cavity to the planned exit point
2. A scalpel stab incision is made over the tip of the forceps at the exit site
3. The drain is pulled through the stab incision to the external surface
4. The drain is secured with exit sutures

The stab incision is sized to match the drain diameter tight enough that the drain does not slide freely but not so tight that it impedes drainage.

How drains are secured: suture technique at the exit

Penrose drain

DVM360: "1 or 2 simple interrupted nonabsorbable sutures are placed through the drain and into the skin at the exit hole."

The suture passes through the drain material itself and through the skin, holding the drain at the correct depth. The suture should be placed through the last 1 mm of the drain on one side securing it without impeding drainage flow or making removal difficult.

Important: tacking the proximal (deep, internal) end of the Penrose drain inside the wound is done cautiously. DVM360 cautions: "Tacking the proximal aspect of the Penrose drain can only be considered with caution, as this can create a natural tension causing potential for drain breakage deep inside the wound."

Do not fenestrate the Penrose drain. Vettimes: "The drain should not be fenestrated as this will reduce the surface area for capillary flow and increase the risk of tearing at the time of removal."

Jackson-Pratt drain (closed suction)

Two-suture fixation:

1. Purse-string suture at exit: a circular suture around the drain at the exit site, tightened to create a seal around the drain and prevent leakage
2. Chinese finger-trap suture: a wrapping pattern along the external portion of the drain tubing, providing robust fixation that resists the pull of the collection reservoir

Clinician's Brief notes the Chinese finger-trap suture should be easily distinguishable from the primary wound sutures, so it is not accidentally cut at suture removal time.

Primary wound closure around the drain

The primary wound is closed normally in layers subcutaneous closure, then skin above and around the drain, which runs out to its separate exit site.

Key principle: the drain does not pass through any of the primary closure layers. The wound closes completely around the drain, which then tunnels subcutaneously to its separate exit.

For how drain placement relates to the layered closure sequence, see drain placement in layered closure context.

Monitoring drain output at home

VCA Animal Hospitals: "Fluid should be draining from the Penrose drain's end, but the fluid amount should decrease every day. There should not be excessive fresh blood, active bleeding, or increasingly unpleasant, thick, or smelly discharge."

Normal drain output progression:

• Days 1 to 2: serosanguinous (blood-tinged watery fluid), moderate volume
• Days 2 to 4: decreasing volume, clearing toward serous (pale yellow or clear)
• Days 4 to 7: minimal volume, fully serous drain is ready for removal

Signs requiring same-day vet contact:

• Volume increasing rather than decreasing after day 2
• Output becoming purulent (thick, green, or yellow) or foul-smelling
• Fresh active bleeding from the drain
• Drain pulled inward (disappearing under the skin) or pulled outward (partially extruded)

For the post-operative monitoring protocol that includes drain assessment, see post-operative monitoring with drain in place.

Drain removal

Timing: VCA: "Drains should be removed as soon as possible, usually within 2 to 4 days. For larger, more extensive wounds, drains may need to stay in place longer."

Most soft tissue drains are removed at 2 to 7 days. Abdominal drains after peritonitis may remain longer depending on drainage character.

Removal technique:

• Penrose: cut the exit suture(s), pull the drain out with a swift, smooth traction
• Jackson-Pratt: cut the Chinese finger-trap suture, disconnect the reservoir, slide the drain out

Vettimes: "Penrose drains are removed by cutting the single external simple interrupted suture, then swiftly tugging the drain to release the tube from its internal anchorage point."

After removal: the exit hole is not sutured. It heals by second intention typically within 3 to 5 days. Keep the area clean with saline until sealed.

Verify complete removal: count the drain length removed against the length inserted. A retained drain fragment is a serious complication requiring surgical retrieval.

Frequently asked questions

My dog has a drain coming from a separate hole next to the incision. Is that normal?

Yes that is the intended placement. The drain exits through a stab incision separate from the primary wound closure. Having the drain exit away from the main incision protects the primary wound from dehiscence and contamination. Both the main incision and the drain exit site should be monitored.

Can my cat remove the drain at home?

Cats frequently attempt to remove drains. An E-collar must be worn at all times until the drain is removed by the vet. Even with an E-collar, some cats are agile enough to reach wounds check drain integrity twice daily. If the drain has been dislodged, contact your vet the same day.

Why doesn't the vet just suture the drain hole closed after the drain comes out?

The exit tract is left to heal by second intention because suturing it closed traps any residual fluid or bacteria that may be present in the tract. Healing open allows this to drain and epithelialize naturally. The resulting healed site is typically a small, flat scar.

Surgical drains work only when the closure around them maintains what the drain is trying to accomplish: fluid exits through the drain, not through a compromised wound closure. The separate exit site, the correct fixation sutures, and the correct coverage all of these protect both the drain's function and the primary wound's integrity simultaneously.

Resources

• Clinician's Brief. Wound Drain Placement: Step-by-Step Veterinary Guide. cliniciansbrief.com
• DVM360. Surgical Drains Are Useful in Small Animal Wound Management. dvm360.com
• Today's Veterinary Practice. Surgical Drains: Placement, Management, and Removal. todaysveterinarypractice.com
• VCA Animal Hospitals. Penrose Drain Discharge Instructions for Dogs. vcahospitals.com