Wound Reconstruction and Tension – Detailed Study Notes
Case contexts and core idea
Burn therapy and heat-related wounds in animals, focusing on how tissue reacts to manipulation and how known lines of tension influence closure.
Examples of thermal injuries from external heat sources:
Prophylactic dental care case with hot water bottles along the flank causing full-thickness necrosis; wound needed excision perpendicularly to known lines of tension and then reconstruction.
A cranial/caudal wound where a heat source oriented along known lines of tension opened less dramatically.
A dorsal burn case from a heating pad leading to a significant thermal injury; a pink rim around dead tissue indicated new epithelium crawling across, suggesting the burn was not third/fourth degree.
Key observation: Wounds opened dramatically when incisions were perpendicular to known lines of tension; along lines of tension they opened less, enabling reconstruction with less open-wound management.
The concept of known lines of tension will be revisited as a fundamental principle in tissue manipulation and wound planning.
Known lines of tension – core concept
Wounds tend to gape and heal differently depending on orientation relative to lines of tension in the tissue.
Closure parallel to the known lines of tension generally reduces tension and improves outcomes.
Extremity wounds are an exception: they frequently require closure perpendicular to the lines of tension due to tissue distribution and movement.
Practical approach:
Awake, standing animal to assess natural tension in multiple directions.
Lift and approximate surrounding skin in various directions to determine the natural direction of least resistance and best opposed closure.
Plan incisions and closures in reference to known lines of tension.
Visual Guideline: incisions parallel to tension lines tend to scar better and tolerate less gaping; incisions perpendicular to tension lines can permit more tissue to be mobilized in extremities, but risk higher tension in some contexts.
Principles and foundational concepts (Hofstadter/Halstead notes)
Halstead principles (surgical hygiene and tissue handling) underpin wound reconstruction:
Gentle tissue handling
Meticulous control of hemorrhage
Observation of strict aseptic technique
Preservation of blood supply to tissues
Elimination of dead space
Accurate tissue apposition with minimal tension
Hofstadter's principles (as presented in slides) set the stage for primary wound reconstruction, tension management, and wound healing variables.
Primary reconstruction goals:
Reconstruct wound with minimal tension
Restore full function and normal range of motion
Achieve good skin coverage and pain-free final outcome
Cost effectiveness and owner satisfaction
Primary closure is ideal when feasible, but many clinical cases default to open wound management; the goal remains to maximize opportunities for primary closure when feasible.
Important ethical/clinical point: aim to save limbs whenever possible and practical, acknowledging higher costs and potential complications.
Wound types and case illustrations (conceptual summaries)
Lovin’/Loving injuries (traumatic soft-tissue injuries): large skin flaps may be pulled but not completely detached; viability must be assessed before closure.
Healed vs non-heals: in cases where tissue viability is questionable, staged reconstructions or open wound management may be preferred until tissue viability improves.
High-risk tissue around joints: articular surfaces require careful planning if fusion or arthrodesis is contemplated.
Pressure-related elbow lesions (Hi grandma lesions): occur in younger animals exposed to hard substrates; begin as pressure points under elbow, progress to calluses; avoid aggressive resection of tissue.
Releasing incision concept: incisions made next to a wound to borrow skin and allow primary closure after undermining in-between.
Specific injury patterns and management strategies
Shearing injuries (pelvic limb, tarsal joint): common after car-related trauma; may cause subluxation or luxation with ruptured ligaments; require soft-tissue management and stabilization of the tarsal joint (cast or splint).
Pelvic limb shearing injury management:
If tarsal joint is unstable, immobilize with a cast or splint; direct immobilization is often done with a lateral splint for pelvic limbs and a caudal/palmar splint for thoracic limbs.
Loven/cheering (loved and torn) injuries: caution about tissue viability in large skin flaps; if the flap is too swollen or compromised, staged management may be needed.
Skin flap viability considerations:
If the flap has compromised vasculature, close monitoring is required; you may attempt primary closure only if the wound bed is healthy.
In many cases, you will plan for open wound management with staged reconstruction rather than immediate primary closure.
Reconstruction strategies and anatomy of closure
Arthrodesis vs arthrodesis-related concepts:
When articular surfaces are exposed or damaged, options include surgical arthrodesis (fusion) with removal of articular cartilage, alignment at a fixed angle, and bone grafting. A bone plate bridges the joint to create a solid column of bone, but skin coverage is essential to prevent infection.
If skin coverage over a fused joint is lacking, the metal hardware tends to harbor bacteria and can be difficult to clear infections; a staged approach with open wound management is preferred.
Transarticular skeletal fixation (TASF):
A transarticular skeletal fixator can be placed across the tarsal joint using pins in the tibia and metatarsals; it stays in place for approximately 8–12 weeks to provide wound access and allow soft tissue to fill in and scar down at a functional angle.
Decision framework for limb preservation:
Always evaluate if limb salvage is possible and preferable to amputation; though costly and with potential complications, limb viability preservation is a major goal.
Special case: elbow hi grandmas and subcutaneous patterns
Benign elbow lesions around pressure points can be managed with environmental modifications and protective braces (Dog Legs brace is mentioned as a practical option).
Avoid aggressive surgical resection of elbow lesions due to risk of infection and poor functional outcomes.
Primary wound closure and related decision criteria
Wound size and planning:
Wounds larger than about 5 cm are more challenging to reconstruct primarily and often require adjunct tools or staged approaches.
Tissue viability and infection status:
Acute vs chronic, infected vs non-infected tissue affects decisions about primary closure vs open wound management and undermining strategies.
Species and breed considerations:
Cats have lower cutaneous perfusion than dogs and are at higher risk for early wound breakdown; take longer to retain sutures and rely more on subcutaneous vascular supply.
Greyhounds and sight-hound breeds have very delicate skin that bruises easily and have higher risk of wound healing complications.
Patient and owner factors:
Owner expectations and financial considerations influence the reconstructive plan and potential for staged procedures.
Surgical planning and suturing approach:
In general, aim to place sutures with minimal tension; consider using intradermal closures in appropriate cases.
Suture materials, patterns, and techniques for tension management
Suture sizing and patterns:
Subcutaneous sutures: typically kept at or below size 3; larger animals or highly under-tension areas may require different sizing.
Skin sutures: prefer suture sizes not exceeding about 3-0 for routine closures; large animals or high-tension wounds may require different choices.
Suture pattern options for tension relief:
Mattress patterns are tension-relieving patterns and are used when closure is under significant tension.
Vertical mattress is preferred over horizontal mattress in high-tension wounds to reduce vascular compromise; a vertical mattress better preserves blood supply than a horizontal mattress bite.
Far-far near-near and near-near far-far patterns are tension-relieving and may be used to oppose wound edges.
Bolsters and adjuncts for tension relief:
Use bolsters (Penrose drain or red rubber catheter) to allow tension-relieving sutures to be tightened without concentrating force on skin edges.
Techniques for avoiding skin damage with tension-relieving sutures:
When using tension-relieving sutures, consider placing them over a bolster to avoid tissue compression and ischemia.
Intradermal (intradermal) skin closure:
Increasingly taught and practiced; practice with a silicone skin model (e.g., Artemis model) to emulate live tissue handling.
Use cutting needles rather than tape or other tools for intradermal layering; ensure proper needle selection for tissue density.
Do not place adhesive glue below the skin level to avoid subcutaneous granulomas and tissue reaction.
Tape and glue:
Cyanoacrylate (medical super glue) can be used to seal small gaps in intradermal closures, but avoid glue seeping into subcutaneous tissue.
Tissue reactivity considerations:
Additional throws and larger tages (tags) can increase tissue inflammation and delay healing; plan carefully before extending throws or increasing tag length.
Practical example considerations:
A vermiform releasing incision technique can be used to borrow skin from adjacent areas and facilitate primary closure; multiple small releasing incisions can be used instead of a single long incision.
Undermining techniques for tension relief
Purpose of undermining:
Release skin and deep tissue attachments to create dead space that allows tissue to stretch and close with less tension.
Methods:
Blunt undermining: use scissors or other tools to separate tissues along natural planes, preserving vessels where possible.
Sharp undermining: use surgical scissors to transect tissue attachments when necessary.
Combined approach:
Most cases require a combination of blunt and sharp undermining to maximize tissue mobility while preserving vasculature.
Precautions:
Preserve direct cutaneous vessels necessary for fusing that area.
Avoid aggressive undermining when tissue is bruised or necrotic; unhealthy tissue should not be undermined aggressively.
Visual for technique:
Demonstrative video shows how undermining around a large thigh wound is performed to gain the necessary mobility for closure.
Releasing incisions and their role in reconstruction
Concept:
Releasing incisions are made adjacent to a wound to borrow tissue; undermining occurs in between to allow closure of both wounds.
Practical considerations:
Large releasing incisions can be used with definitive closure afterwards; multiple small punctate releasing incisions are options to minimize tissue disruption while achieving closure.
Practical notes on surgical planning and decision-making
Size and shape influence closure strategy:
Wounds’ shape and location influence the closure pattern; extremities require special consideration due to limited tissue.
Acute vs chronic wounds and infection status:
Infected acute wounds require careful planning and often staged debridement/open wound management.
Patient factors:
Species differences, age, weight, and breed influence healing capacity and complication risk.
Owner factors:
Willingness and ability to comply with postoperative care and follow-up influence treatment choices.
Other important surgical contexts and cautions
Gunshot injuries and ballistic literature:
Ballistics literature exists but typically focuses on human trauma; in veterinary practice, principles of open wound management apply.
Do not over-resect elbow Hi Grandmas lesions:
In many cases, surgical resection leads to poor outcomes due to infection risk and joint instability; environmental management and protective measures are preferred.
Drainage and seroma concepts:
Seroma (aroma) forms in surgical wounds where tissue planes are created without drains; managing with drains and appropriate wound care is important.
Week-by-week learning and practice emphasis
Week focus on wound reconstruction and skin flaps; skimming over skin grafts in class with separate skin graft lectures for future reference.
Emphasis on practice in intradermal skin closure and anatomic practice models to translate to live animal surgery.
Emphasis on practicing aseptic technique, meticulous hemorrhage control, and tissue handling as core surgical skills.
Final thoughts and clinical takeaways
The central message: tension is the single most important factor determining success in primary wound closure. Minimize tension to prevent ischemia and edge necrosis.
Always consider the known lines of tension when planning incisions and closures to optimize outcomes.
When closure would impose excessive tension, employ undermining, releasing incisions, tension-relieving suture patterns, or staged reconstruction to reduce risk.
Prioritize limb-sparing strategies when feasible, even if they require more time and resources, and discuss realistic outcomes with the owner.
Remember Halstead’s principles and uphold strict aseptic technique as the foundation of successful surgical reconstruction.
Quick reference: key numeric guidelines and terms
Wound closure considerations:
Wounds > 5 cm: more likely to require ancillary tools or staged reconstruction.
TASF duration: typically 8–12 weeks.
Suture sizing and materials:
Subcutaneous suture: generally not larger than 3 (e.g., 3-0, 3-0–4-0 depending on context).
Skin sutures: usually not above 3-0 in many settings; larger animals may require adjustments.
Monochrome (monocryl-like) or polydioxanone (PDS) are common rapidly or moderately absorbable options for subcutaneous closure.
Suturing patterns for tension relief:
Vertical mattress preferred over horizontal mattress in high-tension wounds to reduce vascular compromise.
Far-near and near-far patterns are tension-relieving; they may be used with bolsters.
Intradermal closure practice:
Cutting needle recommended for intradermal work; avoid glues that migrate into subcutaneous tissue.
Intradermal closure practice essential in modern practice; silicone models facilitate skill development.
Tissue management specifics:
Avoid extensive subcutaneous debridement in cats due to poorer cutaneous perfusion and increased risk of wound dehiscence.
Environmental aids:
Braces (e.g., Dog Legs) to prevent recurrent compression injuries and protect tissue integrity.
Consolidated take-home messages
Understand and apply known lines of tension to all wound reconstructions; orient incisions to parallel tension lines when possible, with care for extremities where perpendicular closure may be advantageous.
Use undermining and releasing incisions to minimize tension and preserve tissue viability; plan to borrow tissue only where adequate skin redundancy exists.
Use tension-relieving sutures thoughtfully, with bolsters to protect skin; consider sequential steps and staged closure when necessary.
Favor limb salvage when possible and practical; educate clients about prognosis, risks, and costs.
Maintain Halstead/Hofstadter principles throughout all stages: asepsis, gentle tissue handling, meticulous hemostasis, and careful tissue preservation.
Practice intradermal skin closure and other advanced techniques in models before applying them in live patients to improve outcomes and reduce complications.