16.2 Principles of Oral Surgery, Suturing, Wound Healing and Biopsy Techniques
Key Takeaways
A mucoperiosteal flap must have a base wider than its free margin for blood supply, be large enough for access, rest on sound bone at closure, and avoid nerves such as the mental and lingual nerves.
Excisional biopsy suits small lesions (generally under about 1 cm) that look benign and removes the lesion with a margin of normal tissue; incisional biopsy samples a representative area of large or suspicious lesions, including adjacent normal tissue and avoiding necrotic centers.
Local anesthetic is injected around, not into, a lesion to avoid distorting the tissue, and specimens are handled gently at their edges to prevent crush artifact.
Routine biopsy specimens go into 10% neutral buffered formalin at roughly 20 times the specimen volume; specimens for direct immunofluorescence in suspected pemphigus or pemphigoid go fresh or in Michel's transport medium, never formalin.
A radiolucent jaw lesion is aspirated before it is opened, to exclude a vascular lesion and to obtain fluid that helps diagnosis.
Many SDLE questions ask for the "next step" before surgery: how to design the flap, which biopsy to choose, how to submit the specimen. These principles apply across exodontia, periodontal surgery, implant surgery and soft-tissue procedures.
Core Surgical Principles
- Asepsis: sterile instruments, surgical hand antisepsis, sterile gloves and drapes, and sterile irrigant.
- Adequate access and visibility: retraction, light, suction and a properly designed flap.
- Atraumatic tissue handling: a single firm incision down to bone, sharp instruments, minimal crushing, keeping tissues moist.
- Hemostasis: pressure, local anesthetic with vasoconstrictor, ligation or cautery of vessels, local hemostatic agents.
- Elimination of dead space: layered closure or pressure dressings to prevent hematoma.
- Decontamination and debridement: remove debris, bone fragments and granulation tissue; irrigate copiously.
- Control of edema and pain: cold packs for the first 24-48 hours, analgesics, sometimes a short corticosteroid course.
- Patient general health: medical status, nutrition and medications influence healing.
Flap Design
| Principle | Reason |
|---|---|
| Base wider than the free margin | Preserves the blood supply |
| Adequate size; releasing incisions as needed | Access without tearing; tension-free closure |
| Releasing incisions at line angles, not across bony prominences or over the defect | Avoids recession, clefts and breakdown |
| Margins rest on sound bone at closure | Supports healing and avoids wound dehiscence |
| Full-thickness (mucoperiosteal) when bone access is needed | Periosteum carries blood supply and osteogenic cells |
| Avoid vital structures | Mental nerve (premolar region), lingual nerve (third molar region), greater palatine vessels, submandibular duct |
Common designs: envelope (sulcular, no releasing incision), triangular (one releasing incision), trapezoidal (two releasing incisions), and semilunar (for apical access, now used less).
Suturing
| Material | Type | Approximate behavior | Typical use |
|---|---|---|---|
| Plain gut | Absorbable, natural | Loses strength within about a week | Short-term mucosal closure |
| Chromic gut | Absorbable, natural (chromium-treated) | Lasts somewhat longer than plain gut | Mucosa |
| Polyglactin 910 | Absorbable, synthetic braided | Holds strength for about 2-3 weeks | Extraction sites, flaps |
| Silk | Non-absorbable, braided | Wicks bacteria; remove at about 5-7 days | Traditional intraoral sutures |
| Nylon, polypropylene | Non-absorbable monofilament | Low tissue reaction | Skin, implant and periodontal surgery |
Intraoral closures commonly use 3-0 or 4-0 sutures (finer 5-0 or 6-0 for delicate periodontal and esthetic work) on a reverse-cutting 3/8-circle needle. Techniques: simple interrupted (most common), continuous, horizontal mattress (everts edges and holds grafts or socket margins), vertical mattress, and figure-of-eight across an extraction socket to hold a hemostatic sponge. Use a surgeon's knot, place knots away from the incision line, and do not over-tighten.
Healing of Wounds and Extraction Sockets
- Primary intention: wound edges closely apposed; faster healing, less scarring.
- Secondary intention: a gap fills with granulation tissue (extraction sockets, gingivectomy); slower with more contraction.
- Extraction socket: blood clot in the first hours; granulation tissue replaces it during the first week; epithelium covers the socket over roughly 2-4 weeks; woven bone fills the socket over the following weeks, and remodeling and radiographic fill continue for several months. The buccal plate resorbs most, so ridge width shrinks.
Biopsy
Indications: any lesion persisting more than about 2 weeks after removing a likely irritant, unexplained ulcers, red or speckled patches, white patches at high-risk sites, persistent swellings, unexplained radiolucencies or radiopacities, changing pigmented lesions, and lesions where a clinical diagnosis must be confirmed (for example vesiculobullous disease).
| Technique | Use | Key points |
|---|---|---|
| Excisional | Small (generally under about 1 cm), clinically benign lesions | Remove whole lesion with a margin of normal tissue (commonly about 2-3 mm); elliptical incision about 3 times as long as wide |
| Incisional | Large lesions or suspected malignancy | Sample the most representative and suspicious area, including adjacent normal tissue, avoiding necrotic centers; several sites if the lesion varies |
| Punch | Mucosal lesions, vesiculobullous disease | 4-6 mm punch through epithelium and connective tissue |
| Aspiration | Radiolucent jaw lesions, fluctuant swellings | Aspirate before opening a radiolucency to exclude vascular lesions; straw fluid suggests a cyst, keratin a keratocyst, blood a vascular lesion |
| Fine-needle aspiration | Neck masses, salivary tumors | Cytology, often ultrasound-guided |
| Brush cytology | Screening adjunct | Not a substitute for a scalpel biopsy |
Technique details
- Inject local anesthetic around the lesion, not into it.
- Grasp the specimen at its edge or with a traction suture to avoid crush artifact; avoid electrosurgery at the margins (heat artifact).
- Place routine specimens immediately in 10% neutral buffered formalin (about 20 times the specimen volume).
- For direct immunofluorescence in suspected pemphigus or pemphigoid, take perilesional tissue and send it fresh or in Michel's medium, because formalin destroys the antigens.
- Complete the request form with history, site, size, duration, clinical description and differential diagnosis; mark orientation with a suture if margins matter.
- Arrange follow-up and explain to the patient when and how results will be discussed.
Exam Traps
- Injecting anesthetic directly into the lesion distorts histology.
- An incisional biopsy taken only from a necrotic ulcer center often shows no diagnostic tissue.
- Formalin is wrong for immunofluorescence specimens.
A 2.5 cm indurated ulcer on the lateral border of the tongue of a 60-year-old smoker has persisted for six weeks. Which biopsy is most appropriate?
Fine-needle aspiration of the ulcer center to obtain cells without any incision
Excisional biopsy with 2 mm margins, because every ulcer should be fully removed at first visit
Brush cytology alone, because a negative result rules out squamous carcinoma
Incisional biopsy of the most suspicious area including adjacent normal tissue
A biopsy is planned to confirm suspected mucous membrane pemphigoid. How should the specimen for direct immunofluorescence be handled?
Place it in tap water so the antigens are preserved for staining
Take perilesional tissue and send it fresh or in Michel's medium
Fix it in 10% neutral buffered formalin like any routine biopsy
Take tissue only from the center of an ulcer and freeze it at home
A well-defined unilocular radiolucency is found in the anterior mandible of a 30-year-old. Before surgical exploration, what should be done?
Open it immediately with a large flap, because aspiration spreads tumor cells widely
Inject local anesthetic directly into the lesion to reduce bleeding during exploration
Aspirate the lesion with a needle to exclude a vascular lesion and sample its contents
Treat with antibiotics for two weeks, because all radiolucencies are infections
Sections you finish are checked off in the contents.