NEET MDS Lessons
Oral and Maxillofacial Surgery
Management of Greenstick/Crack Fractures of the Mandible
Greenstick fractures (or crack fractures) are incomplete fractures that typically occur in children due to the flexibility of their bones. Fracture in mandible, can often be managed conservatively, especially when there is no malocclusion (misalignment of the teeth).
Conservative Management
- No Fixation Required:
- For greenstick fractures without malocclusion, surgical fixation is generally not necessary.
- Closed Reduction: The fracture can be managed through closed reduction, which involves realigning the fractured bone without surgical exposure.
- Dietary Recommendations:
- Patients are advised to consume soft foods and maintain adequate hydration with lots of fluids to facilitate healing and minimize discomfort during eating.
Surgical Management Options
In cases where surgical intervention is required, or for more complex fractures, the following methods can be employed:
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Kirschner Wire (K-wire) Fixation:
- Indications: K-wires can be used for both dentulous (having teeth) and edentulous (without teeth) mandibles.
- Technique: K-wires are inserted through the bone fragments to stabilize the fracture. This method provides internal fixation and helps maintain alignment during the healing process.
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Circumferential Wiring:
- Indications: This technique is also applicable for both dentulous and edentulous mandibles.
- Technique: Circumferential wiring involves wrapping wire around the mandible to stabilize the fracture. This method can provide additional support and is often used in conjunction with other fixation techniques.
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External Pin Fixation:
- Indications: Primarily used for edentulous mandibles.
- Technique: External pin fixation involves placing pins into the bone that are connected to an external frame. This method allows for stabilization of the mandible while avoiding intraoral fixation, which can be beneficial in certain clinical scenarios.
Types of Hemorrhage
Hemorrhage, or excessive bleeding, can occur during and after surgical procedures. Understanding the different types of hemorrhage is crucial for effective management and prevention of complications. The three main types of hemorrhage are primary, reactionary, and secondary hemorrhage.
1. Primary Hemorrhage
- Definition: Primary hemorrhage refers to bleeding that occurs at the time of surgery.
- Causes:
- Injury to blood vessels during the surgical procedure.
- Inadequate hemostasis (control of bleeding) during the operation.
- Management:
- Immediate control of bleeding through direct pressure, cauterization, or ligation of blood vessels.
- Use of hemostatic agents or sutures to secure bleeding vessels.
- Clinical Significance: Prompt recognition and management of primary hemorrhage are essential to prevent significant blood loss and ensure patient safety during surgery.
2. Reactionary Hemorrhage
- Definition: Reactionary hemorrhage occurs within a few hours after surgery, typically when the initial vasoconstriction of damaged blood vessels subsides.
- Causes:
- The natural response of blood vessels to constrict after injury may initially control bleeding. However, as the vasoconstriction diminishes, previously damaged vessels may begin to bleed again.
- Movement or changes in position of the patient can also contribute to the reopening of previously clamped vessels.
- Management:
- Monitoring the patient closely in the immediate postoperative period for signs of bleeding.
- If reactionary hemorrhage occurs, surgical intervention may be necessary to identify and control the source of bleeding.
- Clinical Significance: Awareness of the potential for reactionary hemorrhage is important for postoperative care, as it can lead to complications if not addressed promptly.
3. Secondary Hemorrhage
- Definition: Secondary hemorrhage refers to bleeding that occurs up to 14 days postoperatively, often as a result of infection or necrosis of tissue.
- Causes:
- Infection at the surgical site can lead to tissue breakdown and erosion of blood vessels, resulting in bleeding.
- Sloughing of necrotic tissue may also expose blood vessels that were previously protected.
- Management:
- Careful monitoring for signs of infection, such as increased pain, swelling, or discharge from the surgical site.
- Surgical intervention may be required to control bleeding and address the underlying infection.
- Antibiotic therapy may be necessary to treat the infection and prevent further complications.
- Clinical Significance: Secondary hemorrhage can be a serious complication, as it may indicate underlying issues such as infection or inadequate healing. Early recognition and management are crucial to prevent significant blood loss and promote recovery.
Augmentation of the Inferior Border of the Mandible
Mandibular augmentation refers to surgical procedures aimed at increasing the height or contour of the mandible, particularly the inferior border. This type of augmentation is often performed to improve the support for dentures, enhance facial aesthetics, or correct deformities. Below is an overview of the advantages and disadvantages of augmenting the inferior border of the mandible.
Advantages of Inferior Border Augmentation
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Preservation of the Vestibule:
- The procedure does not obliterate the vestibule, allowing for the immediate placement of an interim denture. This is particularly beneficial for patients who require prosthetic support soon after surgery.
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No Change in Vertical Dimension:
- Augmentation of the inferior border does not alter the vertical dimension of the occlusion, which is crucial for maintaining proper bite relationships and avoiding complications associated with changes in jaw alignment.
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Facilitation of Secondary Vestibuloplasty:
- The procedure makes subsequent vestibuloplasty easier. By maintaining the vestibular space, it allows for better access and manipulation during any future surgical interventions aimed at deepening the vestibule.
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Protection of the Graft:
- The graft used for augmentation is not subjected to direct masticatory forces, reducing the risk of graft failure and promoting better healing. This is particularly important in ensuring the longevity and stability of the augmentation.
Disadvantages of Inferior Border Augmentation
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Extraoral Scar:
- The procedure typically involves an incision that can result in an extraoral scar. This may be a cosmetic concern for some patients, especially if the scar is prominent or does not heal well.
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Potential Alteration of Facial Appearance:
- If the submental and submandibular tissues are not initially loose, there is a risk of altering the facial appearance. Tight or inelastic tissues may lead to distortion or asymmetry postoperatively.
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Limited Change in Superior Surface Shape:
- The augmentation primarily affects the inferior border of the mandible and may not significantly change the shape of the superior surface of the mandible. This limitation can affect the overall contour and aesthetics of the jawline.
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Surgical Risks:
- As with any surgical procedure, there are inherent risks, including infection, bleeding, and complications related to anesthesia. Additionally, there may be risks associated with the grafting material used.
Alcohols as Antiseptics
Ethanol and isopropyl alcohol are commonly used as antiseptics in various healthcare settings. They possess antibacterial properties and are effective against a range of microorganisms, although they have limitations in their effectiveness against certain pathogens.
Mechanism of Action
- Antibacterial Activity: Alcohols exhibit antibacterial activity against both gram-positive and gram-negative bacteria, including Mycobacterium tuberculosis.
- Protein Denaturation: The primary mechanism by which alcohols exert their antimicrobial effects is through the denaturation of proteins. This disrupts cellular structures and functions, leading to cell death.
Effectiveness and Recommendations
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Contact Time:
- According to Spaulding (1939), for alcohol to achieve maximum effectiveness, it must remain in contact with the microorganisms for at least 10 minutes. This extended contact time is crucial for ensuring adequate antimicrobial action.
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Concentration:
- Solutions of 70% alcohol are more effective than higher concentrations (e.g., 90% or 100%). The presence of water in the 70% solution enhances the denaturation process of proteins, as reported by Lawrence and Block (1968). Water acts as a co-solvent, allowing for better penetration and interaction with microbial cells.
Hemostatic Agents
Hemostatic agents are critical in surgical procedures to control bleeding and promote wound healing. Various materials are used, each with unique properties and mechanisms of action. Below is a detailed overview of some commonly used hemostatic agents, including Gelfoam, Oxycel, Surgical (Oxycellulose), and Fibrin Glue.
1. Gelfoam
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Composition: Gelfoam is made from gelatin and has a sponge-like structure.
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Mechanism of Action:
- Gelfoam does not have intrinsic hemostatic properties; its hemostatic effect is primarily due to its large surface area, which comes into contact with blood.
- When Gelfoam absorbs blood, it swells and exerts pressure on the bleeding site, providing a scaffold for the formation of a fibrin network.
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Application:
- Gelfoam should be moistened in saline or thrombin solution before application to ensure optimal performance. It is essential to remove all air from the interstices to maximize its effectiveness.
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Absorption: Gelfoam is absorbed by the body through phagocytosis, typically within a few weeks.
2. Oxycel
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Composition: Oxycel is made from oxidized cellulose.
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Mechanism of Action:
- Upon application, Oxycel releases cellulosic acid, which has a strong affinity for hemoglobin, leading to the formation of an artificial clot.
- The acid produced during the wetting process can inactivate thrombin and other hemostatic agents, which is why Oxycel should be applied dry.
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Limitations:
- The acid produced can inhibit epithelialization, making Oxycel unsuitable for use over epithelial surfaces.
3. Surgical (Oxycellulose)
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Composition: Surgical is a glucose polymer-based sterile knitted fabric created through the controlled oxidation of regenerated cellulose.
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Mechanism of Action:
- The local hemostatic mechanism relies on the binding of hemoglobin to oxycellulose, allowing the dressing to expand into a gelatinous mass. This mass acts as a scaffold for clot formation and stabilization.
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Application:
- Surgical can be applied dry or soaked in thrombin solution, providing flexibility in its use.
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Absorption: It is removed by liquefaction and phagocytosis over a period of one week to one month. Unlike Oxycel, Surgical does not inhibit epithelialization and can be used over epithelial surfaces.
4. Fibrin Glue
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Composition: Fibrin glue is a biological adhesive that contains thrombin, fibrinogen, factor XIII, and aprotinin.
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Mechanism of Action:
- Thrombin converts fibrinogen into an unstable fibrin clot, while factor XIII stabilizes the clot. Aprotinin prevents the degradation of the clot.
- During wound healing, fibroblasts migrate through the fibrin meshwork, forming a more permanent framework composed of collagen fibers.
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Applications:
- Fibrin glue is used in various surgical procedures to promote hemostasis and facilitate tissue adhesion. It is particularly useful in areas where traditional sutures may be challenging to apply.
Management and Treatment of Le Fort Fractures
Le Fort fractures require careful assessment and management to restore facial anatomy, function, and aesthetics. The treatment approach may vary depending on the type and severity of the fracture.
Le Fort I Fracture
Initial Assessment:
- Airway Management: Ensure the airway is patent, especially if there is significant swelling or potential for airway compromise.
- Neurological Assessment: Evaluate for any signs of neurological injury.
Treatment:
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Non-Surgical Management:
- Observation: In cases of non-displaced fractures, close monitoring may be sufficient.
- Pain Management: Analgesics to manage pain.
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Surgical Management:
- Open Reduction and Internal Fixation (ORIF): Indicated for displaced fractures to restore occlusion and facial symmetry.
- Maxillomandibular Fixation (MMF): May be used temporarily to stabilize the fracture during healing.
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Postoperative Care:
- Follow-Up: Regular follow-up to monitor healing and occlusion.
- Oral Hygiene: Emphasize the importance of maintaining oral hygiene to prevent infection.
Le Fort II Fracture
Initial Assessment:
- Airway Management: Critical due to potential airway compromise.
- Neurological Assessment: Evaluate for any signs of neurological injury.
Treatment:
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Non-Surgical Management:
- Observation: For non-displaced fractures, close monitoring may be sufficient.
- Pain Management: Analgesics to manage pain.
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Surgical Management:
- Open Reduction and Internal Fixation (ORIF): Required for displaced fractures to restore occlusion and facial symmetry.
- Maxillomandibular Fixation (MMF): May be used to stabilize the fracture during healing.
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Postoperative Care:
- Follow-Up: Regular follow-up to monitor healing and occlusion.
- Oral Hygiene: Emphasize the importance of maintaining oral hygiene to prevent infection.
Le Fort III Fracture
Initial Assessment:
- Airway Management: Critical due to potential airway compromise and significant facial swelling.
- Neurological Assessment: Evaluate for any signs of neurological injury.
Treatment:
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Non-Surgical Management:
- Observation: In cases of non-displaced fractures, close monitoring may be sufficient.
- Pain Management: Analgesics to manage pain.
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Surgical Management:
- Open Reduction and Internal Fixation (ORIF): Essential for restoring facial anatomy and occlusion. This may involve complex reconstruction of the midface.
- Maxillomandibular Fixation (MMF): Often used to stabilize the fracture during healing.
- Craniofacial Reconstruction: In cases of severe displacement or associated injuries, additional reconstructive procedures may be necessary.
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Postoperative Care:
- Follow-Up: Regular follow-up to monitor healing, occlusion, and any complications.
- Oral Hygiene: Emphasize the importance of maintaining oral hygiene to prevent infection.
- Physical Therapy: May be necessary to restore function and mobility.
General Considerations for All Le Fort Fractures
- Antibiotic Prophylaxis: Consideration for prophylactic antibiotics to prevent infection, especially in open fractures.
- Nutritional Support: Ensure adequate nutrition, especially if oral intake is compromised.
- Psychological Support: Address any psychological impact of facial injuries, especially in pediatric patients.
Odontogenic Keratocyst (OKC)
The odontogenic keratocyst (OKC) is a unique and aggressive cystic lesion of the jaw with distinct histological features and a high recurrence rate. Below is a comprehensive overview of its characteristics, treatment options, and prognosis.
Characteristics of Odontogenic Keratocyst
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Definition and Origin:
- The term "odontogenic keratocyst" was first introduced by Philipsen in 1956. It is believed to originate from remnants of the dental lamina or basal cells of the oral epithelium.
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Biological Behavior:
- OKCs exhibit aggressive behavior and have a recurrence rate of 13% to 60%. They are considered to have a neoplastic nature rather than a purely developmental origin.
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Histological Features:
- The cyst lining is typically 6 to 10 cells thick, with a palisaded basal cell layer and a surface of corrugated parakeratin.
- The epithelium may produce orthokeratin (10%), parakeratin (83%), or both (7%).
- No rete ridges are present, and mitotic activity is frequent, contributing to the cyst's growth pattern.
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Types:
- Orthokeratinized OKC: Less aggressive, lower recurrence rate, often associated with dentigerous cysts.
- Parakeratinized OKC: More aggressive with a higher recurrence rate.
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Clinical Features:
- Age: Peak incidence occurs in individuals aged 20 to 30 years.
- Gender: Predilection for males (approximately 1:5 male to female ratio).
- Location: More commonly found in the mandible, particularly in the ramus and third molar area. In the maxilla, the third molar area is also a common site.
- Symptoms: Patients may be asymptomatic, but symptoms can include pain, soft-tissue swelling, drainage, and paresthesia of the lip or teeth.
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Radiographic Features:
- Typically appears as a unilocular lesion with a well-defined peripheral rim, although multilocular varieties (20%) can occur.
- Scalloping of the borders is often present, and it may be associated with the crown of a retained tooth (40%).
Treatment Options for Odontogenic Keratocyst
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Surgical Excision:
- Enucleation: Complete removal of the cyst along with the surrounding tissue.
- Curettage: Scraping of the cyst lining after enucleation to remove any residual cystic tissue.
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Chemical Cauterization:
- Carnoy’s Solution: Application of Carnoy’s solution (6 ml absolute alcohol, 3 ml chloroform, and 1 ml acetic acid) after enucleation and curettage can help reduce recurrence rates. It penetrates the bone and can assist in freeing the cyst from the bone wall.
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Marsupialization:
- This technique involves creating a window in the cyst to allow for drainage and reduction in size, which can be beneficial in larger cysts or in cases where complete excision is not feasible.
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Primary Closure:
- After enucleation and curettage, the site may be closed primarily or packed open to allow for healing.
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Follow-Up:
- Regular follow-up is essential due to the high recurrence rate. Patients should be monitored for signs of recurrence, especially in the first few years post-treatment.
Prognosis
- The prognosis for OKC is variable, with a significant recurrence rate attributed to the aggressive nature of the lesion and the potential for residual cystic tissue.
- Recurrence is not necessarily related to the size of the cyst or the presence of satellite cysts but is influenced by the nature of the lesion itself and the presence of dental lamina remnants.
- Multilocular lesions tend to have a higher recurrence rate compared to unilocular ones.
- Surgical technique does not significantly influence the likelihood of relapse.
Associated Conditions
- Multiple OKCs can be seen in syndromes such as:
- Nevoid Basal Cell Carcinoma Syndrome (Gorlin-Goltz Syndrome)
- Marfan Syndrome
- Ehlers-Danlos Syndrome
- Noonan Syndrome