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Oral and Maxillofacial Surgery - NEETMDS- courses
Oral and Maxillofacial Surgery

Primary Bone Healing and Rigid Fixation

Primary bone healing is a process that occurs when bony fragments are compressed against each other, allowing for direct healing without the formation of a callus. This type of healing is characterized by the migration of osteocytes across the fracture line and is facilitated by rigid fixation techniques. Below is a detailed overview of the concept of primary bone healing, the mechanisms involved, and examples of rigid fixation methods.

Concept of Compression

  • Compression of Bony Fragments: In primary bone healing, the bony fragments are tightly compressed against each other. This compression is crucial as it allows for the direct contact of the bone surfaces, which is necessary for the healing process.

  • Osteocyte Migration: Under conditions of compression, osteocytes (the bone cells responsible for maintaining bone tissue) can migrate across the fracture line. This migration is essential for the healing process, as it facilitates the integration of the bone fragments.

Characteristics of Primary Bone Healing

  • Absence of Callus Formation: Unlike secondary bone healing, which involves the formation of a callus (a soft tissue bridge that eventually hardens into bone), primary bone healing occurs without callus formation. This is due to the rigid fixation that prevents movement between the fragments.

  • Haversian Remodeling: The healing process in primary bone healing involves Haversian remodeling, where the bone is remodeled along the lines of stress. This process allows for the restoration of the bone's structural integrity and strength.

  • Requirements for Primary Healing:

    • Absolute Immobilization: Rigid fixation must provide sufficient stability to prevent any movement (interfragmentary mobility) between the osseous fragments during the healing period.
    • Minimal Gap: There should be minimal distance (gap) between the fragments to facilitate direct contact and healing.

Examples of Rigid Fixation in the Mandible

  1. Lag Screws: The use of two lag screws across a fracture provides strong compression and stability, allowing for primary bone healing.

  2. Bone Plates:

    • Reconstruction Bone Plates: These plates are applied with at least three screws on each side of the fracture to ensure adequate fixation and stability.
    • Compression Plates: A large compression plate can be used across the fracture to maintain rigid fixation and prevent movement.
  3. Proper Application: When these fixation methods are properly applied, they create a stable environment that is conducive to primary bone healing. The rigidity of the fixation prevents interfragmentary mobility, which is essential for the peculiar type of bone healing that occurs without callus formation.

Ludwig's Angina

Ludwig's angina is a serious, potentially life-threatening cellulitis or connective tissue infection of the submandibular space. It is characterized by bilateral swelling of the submandibular and sublingual areas, which can lead to airway obstruction. The condition is named after the German physician Wilhelm Friedrich Ludwig, who provided a classic description of the disease in the early 19th century.

Historical Background

  • Coining of the Term: The term "Ludwig's angina" was first coined by Camerer in 1837, who presented cases that included a classic description of the condition. The name honors W.F. Ludwig, who had described the features of the disease in the previous year.

  • Etymology:

    • The word "angina" is derived from the Latin word "angere," which means "to suffocate" or "to choke." This reflects the potential for airway compromise associated with the condition.
    • The name "Ludwig" recognizes the contributions of Wilhelm Friedrich Ludwig to the understanding of this medical entity.
  • Ludwig's Personal Connection: Interestingly, Ludwig himself died of throat inflammation in 1865, which underscores the severity of infections in the head and neck region.

Clinical Features

Ludwig's angina typically presents with the following features:

  1. Bilateral Swelling: The most characteristic sign is bilateral swelling of the submandibular area, which can extend to the sublingual space. This swelling may cause the floor of the mouth to elevate.

  2. Pain and Tenderness: Patients often experience pain and tenderness in the affected area, which may worsen with movement or swallowing.

  3. Dysphagia and Dysarthria: Difficulty swallowing (dysphagia) and changes in speech (dysarthria) may occur due to swelling and discomfort.

  4. Airway Compromise: As the swelling progresses, there is a risk of airway obstruction, which can be life-threatening. Patients may exhibit signs of respiratory distress.

  5. Systemic Symptoms: Fever, malaise, and other systemic signs of infection may be present.

Etiology

Ludwig's angina is most commonly caused by infections that originate from the teeth, particularly the second or third molars. The infection can spread from dental abscesses or periodontal disease into the submandibular space. The most common pathogens include:

  • Streptococcus species
  • Staphylococcus aureus
  • Anaerobic bacteria

Diagnosis and Management

  • Diagnosis: Diagnosis is primarily clinical, based on the characteristic signs and symptoms. Imaging studies, such as CT scans, may be used to assess the extent of the infection and to rule out other conditions.

  • Management:

    • Airway Management: Ensuring a patent airway is the top priority, especially if there are signs of respiratory distress.
    • Antibiotic Therapy: Broad-spectrum intravenous antibiotics are initiated to target the likely pathogens.
    • Surgical Intervention: In cases of significant swelling or abscess formation, surgical drainage may be necessary to relieve pressure and remove infected material.

1. Radical Neck Dissection

  • Complete removal of all ipsilateral cervical lymph node groups (levels I-V) and three key non-lymphatic structures:
    • Internal jugular vein
    • Sternocleidomastoid muscle
    • Spinal accessory nerve
  • Indication: Typically performed for extensive lymphatic involvement.

2. Modified Radical Neck Dissection

  • Similar to radical neck dissection in terms of lymph node removal (levels I-V) but with preservation of one or more of the following structures:
    • Type I: Preserves the spinal accessory nerve.
    • Type II: Preserves the spinal accessory nerve and the sternocleidomastoid muscle.
    • Type III: Preserves the spinal accessory nerve, sternocleidomastoid muscle, and internal jugular vein.
  • Indication: Used when there is a need to reduce morbidity while still addressing lymphatic involvement.

3. Selective Neck Dissection

  • Preservation of one or more lymph node groups that are typically removed in a radical neck dissection.
  • Classification:
    • Originally had named dissections (e.g., supraomohyoid neck dissection for levels I-III).
    • The 2001 modification proposed naming dissections based on the cancer type and the specific node groups removed. For example, a selective neck dissection for oral cavity cancer might be referred to as a selective neck dissection (levels I-III).
  • Indication: Used when there is a lower risk of lymphatic spread or when targeting specific areas.

4. Extended Neck Dissection

  •  Involves the removal of additional lymph node groups or non-lymphatic structures beyond those included in a radical neck dissection. This may include:
    • Mediastinal nodes
    • Non-lymphatic structures such as the carotid artery or hypoglossal nerve.
  • Indication: Typically performed in cases of extensive disease or when there is a need to address additional areas of concern.

Characteristics of Middle-Third Facial Fractures

Middle-third facial fractures, often referred to as "midfacial fractures," involve the central portion of the face, including the nasal bones, maxilla, and zygomatic arch. These fractures can result from various types of trauma, such as motor vehicle accidents, falls, or physical assaults. The following points highlight the key features and clinical implications of middle-third facial fractures:

1. Oedema of the Middle Third of the Face

  • Rapid Development: Oedema (swelling) in the middle third of the face develops quickly after the injury, leading to a characteristic "balloon" appearance. This swelling is due to the accumulation of fluid in the soft tissues of the face.

  • Absence of Deep Cervical Fascia: The unique anatomical structure of the middle third of the face contributes to this swelling. The absence of deep cervical fascia in this region allows for the rapid spread of fluid, resulting in pronounced oedema.

  • Clinical Presentation: In the early stages following injury, patients with middle-third fractures often present with similar facial appearances due to the characteristic swelling. This can make diagnosis based solely on visual inspection challenging.

2. Lengthening of the Face

  • Displacement of the Middle Third: The downward and backward displacement of the middle third of the facial skeleton can lead to an increase in the overall length of the face. This displacement forces the mandible to open, which can result in a change in occlusion, particularly in the molar region.

  • Gagging of Occlusion: The altered position of the mandible can lead to a malocclusion, where the upper and lower teeth do not align properly. This can cause discomfort and difficulty in chewing or speaking.

  • Delayed Recognition of Lengthening: The true increase in facial length may not be fully appreciated until the initial oedema subsides. As the swelling decreases, the changes in facial structure become more apparent.

3. Nasal Obstruction

  • Blood Clots in the Nares: Following a middle-third fracture, the nares (nostrils) may become obstructed by blood clots, leading to nasal congestion. This can significantly impact the patient's ability to breathe through the nose.

  • Mouth Breathing: Due to the obstruction, patients are often forced to breathe through their mouths, which can lead to additional complications, such as dry mouth and increased risk of respiratory infections.

Submasseteric Space Infection

Submasseteric space infection refers to an infection that occurs in the submasseteric space, which is located beneath the masseter muscle. This space is clinically significant in the context of dental infections, particularly those arising from the lower third molars (wisdom teeth) or other odontogenic sources. Understanding the anatomy and potential spread of infections in this area is crucial for effective diagnosis and management.

Anatomy of the Submasseteric Space

  1. Location:

    • The submasseteric space is situated beneath the masseter muscle, which is a major muscle involved in mastication (chewing).
    • This space is bordered superiorly by the masseter muscle and inferiorly by the lower border of the ramus of the mandible.
  2. Boundaries:

    • Inferior Boundary: The extension of an abscess or infection inferiorly is limited by the firm attachment of the masseter muscle to the lower border of the ramus of the mandible. This attachment creates a barrier that can restrict the spread of infection downward.
    • Anterior Boundary: The forward spread of infection beyond the anterior border of the ramus is restricted by the anterior tail of the tendon of the temporalis muscle, which inserts into the anterior border of the ramus. This anatomical feature helps to contain infections within the submasseteric space.
  3. Posterior Boundary: The posterior limit of the submasseteric space is generally defined by the posterior border of the ramus of the mandible.

Clinical Implications

  1. Sources of Infection:

    • Infections in the submasseteric space often arise from odontogenic sources, such as:
      • Pericoronitis associated with impacted lower third molars.
      • Dental abscesses from other teeth in the mandible.
      • Periodontal infections.
  2. Symptoms:

    • Patients with submasseteric space infections may present with:
      • Swelling and tenderness in the area of the masseter muscle.
      • Limited mouth opening (trismus) due to muscle spasm or swelling.
      • Pain that may radiate to the ear or temporomandibular joint (TMJ).
      • Fever and systemic signs of infection in more severe cases.
  3. Diagnosis:

    • Diagnosis is typically made through clinical examination and imaging studies, such as panoramic radiographs or CT scans, to assess the extent of the infection and its relationship to surrounding structures.
  4. Management:

    • Treatment of submasseteric space infections usually involves:
      • Antibiotic Therapy: Broad-spectrum antibiotics are often initiated to control the infection.
      • Surgical Intervention: Drainage of the abscess may be necessary, especially if there is significant swelling or if the patient is not responding to conservative management. Incision and drainage can be performed intraorally or extraorally, depending on the extent of the infection.
      • Management of the Source: Addressing the underlying dental issue, such as extraction of an impacted tooth or treatment of a dental abscess, is essential to prevent recurrence.

Nasogastric Tube (Ryles Tube)

nasogastric tube (NG tube), commonly referred to as a Ryles tube, is a medical device used for various purposes, primarily involving the stomach. It is a long, hollow tube made of polyvinyl chloride (PVC) with one blunt end and multiple openings along its length. The tube is designed to be inserted through the nostril, down the esophagus, and into the stomach.

Description and Insertion

  • Structure: The NG tube has a blunt end that is inserted into the nostril, and it features multiple openings to allow for the passage of fluids and air. The open end of the tube is used for feeding or drainage.

  • Insertion Technique:

    1. The tube is gently passed through one of the nostrils and advanced through the nasopharynx and into the esophagus.
    2. Care is taken to ensure that the tube follows the natural curvature of the nasal passages and esophagus.
    3. Once the tube is in place, its position must be confirmed before any feeds or medications are administered.
  • Position Confirmation:

    • To check the position of the tube, air is pushed into the tube using a syringe.
    • The presence of air in the stomach is confirmed by auscultation with a stethoscope, listening for the characteristic "whoosh" sound of air entering the stomach.
    • Only after confirming that the tube is correctly positioned in the stomach should feeding or medication administration begin.
  • Securing the Tube: The tube is fixed to the nose using sticking plaster or adhesive tape to prevent displacement.

Uses of Nasogastric Tube

  1. Nutritional Support:

    • Enteral Feeding: The primary use of a nasogastric tube is to provide nutritional support to patients who are unable to take oral feeds due to various reasons, such as:
      • Neurological conditions (e.g., stroke, coma)
      • Surgical procedures affecting the gastrointestinal tract
      • Severe dysphagia (difficulty swallowing)
  2. Gastric Lavage:

    • Postoperative Care: NG tubes can be used for gastric lavage to flush out blood, fluids, or other contents from the stomach after surgery. This is particularly important in cases where there is a risk of aspiration or when the stomach needs to be emptied.
    • Poisoning: In cases of poisoning or overdose, gastric lavage may be performed using an NG tube to remove toxic substances from the stomach. This procedure should be done promptly and under medical supervision.
  3. Decompression:

    • Relieving Distension: The NG tube can also be used to decompress the stomach in cases of bowel obstruction or ileus, allowing for the removal of excess gas and fluid.
  4. Medication Administration:

    • The tube can be used to administer medications directly into the stomach for patients who cannot take oral medications.

Considerations and Complications

  • Patient Comfort: Insertion of the NG tube can be uncomfortable for patients, and proper technique should be used to minimize discomfort.

  • Complications: Potential complications include:

    • Nasal and esophageal irritation or injury
    • Misplacement of the tube into the lungs, leading to aspiration
    • Sinusitis or nasal ulceration with prolonged use
    • Gastrointestinal complications, such as gastric erosion or ulceration

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:

  1. 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.
  2. 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.
  3. 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.

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