Wound Healing Concepts and Classification

Study Notes

Wound Healing Goals

Primary goal: Achieve anatomical integrity and full function of the injured part.
Secondary goal: Achieve the best possible cosmetic result.

Wound Healing Classification

Primary Intention:*
Wound edges are clean and well-approximated.
Healing is rapid, with minimal scar tissue formation.
Usually united within 2 weeks, with dense scar formation within 1 month.
Secondary Intention:*
Wound edges are separated.
Healing occurs from the wound base upward.
Results in more extensive scar tissue formation.
Healing is slower and may lead to wound contracture.

Normal Wound Healing Sequence

Similar process for both primary and secondary intention.
Steps are not detailed in the text.

Factors Affecting Wound Healing

Local Factors:*
Wound Sepsis:
- Shaving skin before surgery increases bacterial counts and worsens infection rates.
- Hair removal should be performed immediately before surgery.
- Thorough antiseptic skin preparation with chlorhexidine or povidone-iodine is crucial.
- Double skin scrubbing is standard procedure in most surgeries.
- Surgeon's hand hygiene with the same antiseptics is important to reduce wound sepsis.
Poor Blood Supply:
- Areas with good vascularity heal faster.
- Surgical technique affects blood supply to the area.
- Maintenance of the vascular supply is critical.
- Appropriate incision planning minimizes vascular disruption.
Wound Tension:
- High tension separates edges, impairs blood supply, and leads to complications.
- Incision planning should minimize tension.
- Skin grafting or flaps may be used to bridge large gaps.
- Incisions along Langer's lines (natural skin creases) improve cosmetic results.
Foreign Bodies:
- Foreign material in the wound increases infection risk and scar formation.
- Traumatic wounds should be thoroughly debrided.
- Surgical wounds should be cleaned to remove devascularized fat, necrotic tissue, or hair.
Previous Irradiation:
- Preoperative radiotherapy damages blood vessels and skin stem cells, impacting healing.
Systemic Factors:*
Nutritional Deficiencies:
- Vitamins A and C are essential for epithelialization and collagen production.
- Zinc is an enzyme cofactor for cell proliferation.
- Protein is needed for collagen production, impaired healing occurs with deficient intake.
Systemic Diseases:
- Diabetes, uremia, and jaundice impair wound healing.
Therapeutic Agents:
- Immunosuppressants (chemotherapy, corticosteroids) inhibit inflammatory response, slowing healing.
- Corticosteroids specifically weaken small blood vessels.
Age:
- Healing rates are higher before puberty.

Complications of Wound Healing

Infection: (Further discussion is needed in the next lecture).
Dehiscence:
- Total separation of the surgical wound layers.
- High mortality rate in abdominal wounds.
- Causes can include suture breakage, knot slippage, suture cutting, excessive tension.
Incisional Hernia:
- Dehiscence of deeper layers, skin intact.
- Visceral (e.g., intestine) protrusion through defect.
- More common in abdominal wounds.
Hypertrophic Scarring:
- Excess collagen scar tissue (non-progressive after 6 months).
- Does not extend beyond edges of the wound.
- Occurs in specific areas (joints, incisions across Langer's lines).
- Poor suturing techniques, overlapping edges can cause hypertrophic scars.
- Difficult to treat.
Keloid Scarring:
- Abnormal collagen metabolism leading to excess scar tissue extending beyond wound edges.
- Continue to enlarge after 6 months.
- Higher frequency in dark-skinned individuals and burn wounds.
- Difficult to treat, recurrence is common.
Contractures:
- Scar tissue shortening, limiting movement, especially at joints.
- More common in wounds with delayed healing, burns.
- Avoid vertical incisions across joints.
- Surgical treatments are required.

Description

This quiz explores the goals and classifications of wound healing, including primary and secondary intention. It covers the normal healing sequence and factors that affect wound healing, particularly local factors like wound sepsis. Test your understanding of these vital concepts in wound management.