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

  • Mandible lever mechanics:
    • Class III lever: Tensile forces at upper surface, compressive forces at lower border.
    • Finite element analysis: Bite force anterior/posterior to fracture → compressive forces at superior border.
  • Lag screw fixation: Provides highest rigidity (2000 – 4000 N compressive force).
  • Titanium plates: Least deflection under MRI; heat production is a concern.
  • Stress shielding: Metallic plates cause atrophic changes due to lack of functional stimuli.
  • Resorbable plates: Made of polydioxanone, polyglycolic acid, polylactic acid; degrade into CO₂ & H₂O via citric acid cycle.

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.

Fixation of Condylar Fractures

Condylar fractures of the mandible can be challenging to manage due to their location and the functional demands placed on the condylar region. Various fixation techniques have been developed to achieve stable fixation and promote healing. Below is an overview of the different methods of fixation for condylar fractures, including their advantages, disadvantages, and indications.

1. Miniplate Osteosynthesis

  • Overview:

    • Miniplate osteosynthesis involves the use of condylar plates and screw systems designed to withstand biochemical forces, minimizing micromotion at the fracture site.
  • Primary Bone Healing:

    • Under optimal conditions of stability and fracture reduction, primary bone healing can occur, allowing new bone to form along the fracture surface without the formation of fibrous tissue.
  • Plate Placement:

    • High condylar fractures may accommodate only one plate with two screws above and below the fracture line, parallel to the posterior border, providing adequate stability in most cases.
    • For low condylar fractures, two plates may be required. The posterior plate should parallel the posterior ascending ramus, while the anterior plate can be angulated across the fracture line.
  • Mechanical Advantage:

    • The use of two miniplates at the anterior and posterior borders of the condylar neck restores tension and compression trajectories, neutralizing functional stresses in the condylar neck.
  • Research Findings:

    • Studies have shown that the double mini plate method is the only system able to withstand normal loading forces in cadaver mandibles.

2. Dynamic Compression Plating

  • Overview:

    • Dynamic compression plating is generally not recommended for condylar fractures due to the oblique nature of the fractures, which can lead to overlap of fragment ends and loss of ramus height.
  • Current Practice:

    • The consensus is that treatment is adequate with miniplates placed in a neutral mode, avoiding the complications associated with dynamic compression plating.

3. Lag Screw Osteosynthesis

  • Overview:

    • First described for condylar fractures by Wackerbauer in 1962, lag screws provide a biomechanically advantageous method of fixation.
  • Mechanism:

    • A true lag screw has threads only on the distal end, allowing for compression when tightened against the near cortex. This central placement of the screw enhances stability.
  • Advantages:

    • Rapid application of rigid fixation and close approximation of fractured parts due to significant compression generated.
    • Less traumatic than miniplates, as there is no need to open the joint capsule.
  • Disadvantages:

    • Risk of lateralization and rotation of the condylar head if the screw is not placed centrally.
    • Requires a steep learning curve for proper application.
  • Contraindications:

    • Not suitable for cases with loss of bone in the fracture gap or comminution that could lead to displacement when compression is applied.
  • Popular Options:

    • The Eckelt screw is one of the most widely used lag screws in current practice.

4. Pin Fixation

  • Overview:

    • Pin fixation involves the use of 1.3 mm Kirschner wires (K-wires) placed into the condyle under direct vision.
  • Technique:

    • This method requires an open approach to the condylar head and traction applied to the lower border of the mandible. A minimum of three convergent K-wires is typically needed to ensure stability.

5. Resorbable Pins and Plates

  • Overview:

    • Resorbable fixation devices may take more than two years to fully resorb. Materials used include self-reinforced poly-L-lactide screws (SR-PLLA), polyglycolide pins, and absorbable alpha-hydroxy polyesters.
  • Indications:

    • These materials are particularly useful in pediatric patients or in situations where permanent hardware may not be desirable.

Anatomy

  • Course: Mandibular foramen → mental foramen
  • Branches: Dental branches, mental nerve, incisive nerve
  • Function: Sensation to mandibular teeth, chin, lower lip
  • Clinical significance: Most commonly injured nerve in oral surgery

Common Injury Scenarios

  • Third molar extraction: Most frequent cause
  • Implant placement: Especially posterior mandible
  • Orthognathic surgery: Bilateral sagittal split osteotomy
  • Mandible fractures: Direct trauma or surgical treatment
  • Local anesthesia: Rare but reported

Repair Considerations

  • Timing: Early repair (within 3-6 months) preferred
  • Surgical approach: Intraoral vs extraoral
  • Magnification: Operating microscope or loupes essential
  • Patient factors: Age, overall health, functional expectations

Surgical Technique for IAN Repair

Preoperative Planning

  • Imaging: CT or MRI to assess defect size
  • Function testing: Baseline sensory evaluation
  • Patient counseling: Realistic expectations

Surgical Steps

  1. Exposure: Careful dissection to identify nerve ends
  2. Debridement: Remove scar tissue and neuromas
  3. Assessment: Determine gap size and repair options
  4. Repair: Direct suture vs grafting based on gap
  5. Closure: Tension-free, layered closure

Postoperative Care

  • Protection: Avoid trauma to surgical site
  • Monitoring: Regular sensory function assessment
  • Rehabilitation: Sensory re-education if appropriate
  • Timeline: Monitor recovery for 18-24 months

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.

LASER THERAPY – VERY HIGH YIELD

Laser Physics & Mechanisms

Q – Switching

  • Creates exceptionally short pulse time
  • Limits lateral tissue damage
  • Used with short thermal relaxation time tissues
  • Example: Ruby laser for tattoo removal

CO₂ Laser Parameters

  • Continuous wave: Coagulation necrosis zone ~500 microns
  • Superpulse/Ultrapulse: Reduces zone to <100 microns

Tissue Interactions (4 Basic Types)

  1. Reflection
  2. Scatter
  3. Transmission
  4. Absorption

Tissue Reactions Post – Absorption (4 Types)

  1. Photothermal
  2. Photoablative
  3. Photochemical
  4. Photoacoustic

Clinical Applications

Cosmetic Skin Resurfacing

  • Primary lasers: CO₂ laser, Er:YAG laser

Laser Delivery Systems

  1. Fiberoptic guide
  2. Articulated arm laser
  3. Hollow wave guide technology (most recent)

Pathophysiology of Tongue Obstruction

  • Mechanism: Loss of muscle tone in unconscious patients
  • Gravity effect: Tongue falls posteriorly, blocks pharynx
  • Risk factors: General anesthesia, sedation, head trauma
  • Critical consideration: Threatens airway patency

Management Options

Non-Invasive Methods (Preferred)

Oropharyngeal Airway (Guedel Airway)
  • Preferred method for tongue control
  • Mechanism: Lifts tongue away from posterior pharynx
  • Sizes: 000 (infant) to 5 (large adult)
  • Insertion: Insert upside down, rotate 180° when reaching soft palate
  • Advantages:
    • No bleeding risk
    • Easy insertion/removal
    • Maintains airway patency
    • Allows spontaneous ventilation
Nasopharyngeal Airway (Trumpet)
  • Alternative: When oropharyngeal airway not tolerated
  • Size: 6-8mm internal diameter for adults
  • Length: Distance from nostril to earlobe
  • Lubrication: Water-soluble lubricant essential
  • Contraindications: Basal skull fracture, severe nasal trauma

Invasive Methods (Higher Risk)

Traction Suture
  • Technique: Suture through tongue tip for anterior traction
  • Risk: May cause bleeding (lingual vessels)
  • Indication: When airways insufficient, surgical access needed
  • Suture: 2-0 silk with curved needle
Towel Clip
  • Technique: Grasp tongue with towel clips for traction
  • Risk: Bleeding from tissue trauma
  • Pain: Significant in conscious patients
  • Use: Limited to specific surgical situations

Clinical Decision Making

  • First line: Oropharyngeal airway (safest, most effective)
  • Avoid: Invasive methods unless absolutely necessary
  • Consider: Patient consciousness level, surgical requirements
  • Monitor: Continuous assessment of airway patency

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