Plastic surgery

• Plastic and Reconstructive Surgery


  Relates to technical aspects of incision planning and wound repair
• These principles apply to all surgical disciplines
• Skin Incisions


  • Skin exists in a resting state of tension caused by gravity and its conformation over underlying structures
  • Traumatic wounds do not permit the same careful planning that is possible with incisions made in undamaged skin
• Incision Repair


  • A well-performed skin incision sets the stage for an accurate repair that minimizes the risk of unfavorable scarring
  • An unfavorable scar is characterized by excessive amount of collagen deposition, leading to hypertrophic scarring or keloid formation
  • Most important layer to approximate is the dermis
  • Contains the healing elements necessary for healing
• Hypertrophic Scar


  Stops growing 6 months after the injury
• Keloid


  • Continues to grow
  • Even growing well beyond its borders
• Phases of Wound Healing

  1. Hemostasis

  2. Inflammation

  3. Proliferation

  4. Tissue remodeling or resolution
• Hemostasis


  • Occurs immediately after tissue injury
  • The most important cells are platelets
• Inflammation


  • Polymorphonuclear leukocytes (PMNs) and macrophages
  • Their primary role is mainly to act as scavengers
  • Aid in phagocytosis and the secretion of free articles that kill bacteria and reduce the bioburden
  • 48 hours of tissue injury
• Macrophage-related functions


  • Phagocytosis
  • Release of reactive oxygen species that result in cellular killing specifically related to bacterial lysis
  • Release of nitric oxide that is deadly to several otherwise antibody-resistant bacteria
  • Cytokine release of interleukins (IL1, IL2, IL4, and IL12)
  • Angiogenesis via VEGF that promotes capillary budding
  • Recruitment of other cells into the wound that continues the healing process
  • Different homeostatic roles of macrophages and Langerhans cells, including wound repair, follicle regeneration, salt balance, and cancer regression and progression in the skin
• Inflammation


  • Inflammatory phase determines the difference between chronic and acute wounds
  • Uncomplicated wounds heal within 4 to 6 weeks
  • Chronic: >6 weeks
• Biofilm


  • Important microbial factor that impedes healing by affecting inflammatory processes
  • Comprises a colony of microorganisms enveloped with a matrix of extracellular polymers
  • Also known as extracellular polymeric substance (EPS)
• Proliferation


  • First step towards restoration of tissue continuity
  • Characterized by the production of extracellular matrix by the fibroblast
  • Fibroblasts are the architects of wound healing and appear in the wound right at the end of the inflammatory phase
• Remodeling/maturation


  • Primarily characterized by the remodeling of collagen through a balance between collagen formation and collagen lysis that results in the formation of a strong scar
  • This phase begins 3 weeks after the injury and continues for over 1 year
  • Scar tissue is weaker than injured skin and regains only 80% of its uninjured tensile strength
• Reconstructive Surgery


  • Restores normal anatomy and function using plastic surgery methods of tissue repair, rearrangement, and replacement
  • The clinical objective is to reestablish normal anatomy, function, and appearance in order to restore the patient as closely as possible to normal health
  • The most useful techniques transfer and modify tissues in the form of tissue grafts and surgical flaps
• Reconstructive Strategies and Methods

  1. Primary intention

  2. Secondary intention

  3. Tertiary intention
• Primary intention


  • Occurs in a clean wound without any apparent tissue loss
  • Typically, this wound seals off within 24 hours
  • Seen in surgical incisions that have been approximated (primary closure)
  • Healing is faster and there is the least amount of scarring
• Secondary intention


  • Tissue loss following major trauma
  • Results in the formation of granulation tissue
  • Results in a broader scar
• Tertiary intention


  • Delayed primary closure or secondary suture
  • The wound is initially cleaned, debrided, and observed, typically 4 or 5 days before closure
• Split-Thickness Grafts


  • STSG is the simplest method of tissue transfer
  • STSG donor sites heal by regeneration from dermal and epidermal elements remaining in the harvest site
• Split-Thickness Grafts


  • Thin grafts
  • Thick grafts
• Thin grafts


  • Harvested through the superficial levels of the dermis
  • Undergo less primary contraction
  • Improved chances of complete engraftment, or "taking,"
  • Contain mostly epidermis, which has low metabolic demands
• Thick grafts


  • Harvested through deeper layers and include a larger amount of dermal tissue
  • Undergo greater amounts of primary contraction
  • Contain more dermis with greater metabolic needs
• Full-Thickness Grafts


  • Include the epidermis and the complete dermis
  • Remove any retained subcutaneous tissue from the deep surface of the dermis in order to maximize the potential for engraftment
  • Associated with the greatest amount of primary contraction
  • Least amount of secondary contraction
  • The highest durability
  • The best cosmetic appearance
  • Work poorly in wounds associated with previous radiation treatments in cancer patients
• Skin Substitutes


  • Typically types of extracellular matrices that are often acellular and are either: human-derived (allografts), animal-derived (xenografts), tissue-engineered, or a combination of the three
  • Employed to replace lost dermal and/or epidermal skin layers
  • Ex. burns, trauma, and other superficial injuries to the outer skin layers
• Graft Take


  1. Imbibition

  2. Inosculation

  3. Revascularization
• Imbibition


  • Takes place during the first 24 to 48 hours
  • The graft is held in place by a thin film of fibrin, and the cellular elements survive by diffusion of oxygen and substrate from plasma present in the open wound
• Inosculation


  • Period during which the graft is most at risk for failure
  • After 48 hours, a fine vascular network forms from capillaries and small blood vessels in the wound bed and advances through the fibrin layer toward the graft
  • Events that can cause graft failure at this time: mechanical shear, formation of a seroma or hematoma, bacterial contamination
• Revascularization


  • The final phase of engraftment
  • Firmer vascular anastomoses are formed as the vessels heal, and the graft becomes perfused from the wound bed
  • 4 to 5 days after graft placement
• Composite Grafts


  • Might include subcutaneous fat, cartilage, perichondrium, and small amounts of muscle
  • The donor site for composite tissue grafts must be repaired with primary closure
  • Indications for composite grafts are limited to small areas with specialized tissue requirements such as nasal reconstruction
• Proximity to the defect

  • Local flaps
  • Regional flaps
  • Distant flaps
• Flap pedicle


  The tissue transmitting the blood supply
• Free flaps


  • The diameter of the blood vessels that supply common surgical flaps is usually less than 5 mm
  • Reconstructive microsurgery
• Random Pattern Flaps


  • Simplest flap designs
  • Named because the blood supply is based on unnamed vessels in the attached base of the flap that perfuse through the subdermal plexus
  • Typically used to reconstruct relatively small, full-thickness defects
  • Designed following geometric principles of skin rearrangement with a traditional length-to-width ratio of 3:1
  • Examples: Transposition flaps, Advancement flaps, Interpolated flaps
• Axial Pattern Flaps


  • These flaps routinely violated the strict limitations of the accepted length-to-width ratio
  • Further investigation demonstrated that these flaps had significant arteries running parallel to the long axis of the flap
  • The earliest example of this type of flap is the deltopectoral flap
• Musculocutaneous Flaps


  • Vascular pattern arises from major vessels that primarily supply a muscle and secondarily supply the skin through multiple small vessels traversing between the superficial surface of the muscle and the subdermal plexus
  • Mathes and Nahai classification: According to the number and dominance of the vascular pedicles supplying each
  • Classic example is breast reconstruction using a latissimus dorsi myocutaneous flap
• Fasciocutaneous Flaps


  • The artery and vein of the flap pedicle passes between rather than through muscles, form a plexus of vessels within the fascia, and then send multiple small vessels to the subdermal plexus to perfuse the skin
  • Thinner compared to musculocutaneous flaps
  • They also do not create a functional loss of muscle in the donor site
  • Ex: sural perforator fasciocutaneous flaps
• Direct Cutaneous Flaps


  Surgical flaps that have a vascular pedicle that reaches directly to the superficial tissues and subdermal plexus without passing through a muscle or fascia plexus
• Perforator Flaps


  These flaps are the result of complementary advances in our understanding of cutaneous blood supply and improved surgical techniques
• Tissue Expansion


  • Technique that increases the amount of tissue in a surgical flap
  • Placing an inflatable device into the tissue beneath the planned flap and gradually expanding the tissue by regular inflation
  • The technique permits reconstruction with tissue of similar color, texture, and thickness, with minimal donor site morbidity