NEET MDS Lessons
General Surgery
TMJ Ankylosis
Temporomandibular Joint (TMJ) ankylosis is a condition characterized by the abnormal fusion of the mandibular condyle to the temporal bone, leading to restricted jaw movement. This condition can significantly impact a patient's ability to open their mouth and perform normal functions such as eating and speaking.
Causes and Mechanisms of TMJ Ankylosis
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Condylar Injuries:
- Most cases of TMJ ankylosis result from condylar injuries sustained before the age of 10. The unique anatomy and physiology of the condyle in children contribute to the development of ankylosis.
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Unique Pattern of Condylar Fractures in Children:
- In children, the condylar cortical bone is thinner, and the condylar neck is broader. This anatomical configuration, combined with a rich subarticular vascular plexus, predisposes children to specific types of fractures.
- Intracapsular Fractures: These fractures can lead to comminution (fragmentation) and hemarthrosis (bleeding into the joint) of the condylar head. A specific type of intracapsular fracture known as a "mushroom fracture" occurs, characterized by the comminution of the condylar head.
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Formation of Fibrous Mass:
- The presence of a highly osteogenic environment (one that promotes bone formation) following a fracture can lead to the organization of a fibrous mass. This mass can undergo ossification (the process of bone formation) and consolidation, ultimately resulting in ankylosis.
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Trauma from Forceps Delivery:
- TMJ ankylosis can also occur due to trauma sustained during forceps delivery, which may cause injury to the condylar region.
Etiology and Risk Factors
Laskin (1978) outlined several factors that may contribute to the etiology of TMJ ankylosis following trauma:
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Age of Patient:
- Younger patients have a significantly higher osteogenic potential and a more rapid healing response. The articular capsule in younger individuals is not as well developed, allowing for easier displacement of the condyle out of the fossa, which can damage the articular disk. Additionally, children may exhibit a greater tendency for prolonged self-imposed immobilization of the mandible after trauma.
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Type of Fracture:
- The condyle in children has a thinner cortex and a thicker neck, which predisposes them to a higher proportion of intracapsular comminuted fractures. In contrast, adults typically have a thinner condylar neck, which usually fractures at the neck, sparing the head of the condyle within the capsule.
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Damage to the Articular Disk:
- Direct contact between a comminuted condyle and the glenoid fossa, either due to a displaced or torn meniscus (articular disk), is a key factor in the development of ankylosis. This contact can lead to inflammation and subsequent bony fusion.
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Period of Immobilization:
- Prolonged mechanical immobilization or muscle splinting can promote orthogenesis (the formation of bone) and consolidation in an injured condyle. Total immobility between articular surfaces after a condylar injury can lead to a bony type of fusion, while some movement may result in a fibrous type of union.
Sinus
It is a tubular track lined by granulation tissue and open at one end which is at the surface,
eg. Tuberculous Sinus
Fistula
A tubular track lined by granulation tissue and open at both ends.at least one of which communicates with a hollow viscus. it can be internal or external.
Causes
1. Inadequate drainage
- Abscess bursting at the non dependent part
- Incision at the non-dependent part.
- Narrow outer opening leading to collection of exudates in the cavity.
2. Presence of foreign body like sequestrum or slough.
3. Persistence of infection.
4. When the track is lined by epithelium
5. Specific causes, TB., Syphilis, etc.
6. Marked fibrosis of the wall with obliteration of blood vessels.
7. Poor general condition causing delayed healing.
Treatment
1. control of specific infection,
2. Thorough excision of track to open up the cavity. Removal of foreign body and scraping of the epithelium
3. Through Scrapping of the wall to expose healthy tissue
4. Wound laid open and allowed to heal from the bottom leaving no pocket,
Intubation
Intubation is a critical procedure in airway management, and the choice of technique—oral intubation, nasal intubation, or tracheostomy—depends on the clinical situation, patient anatomy, and specific indications or contraindications.
Indications for Each Intubation Technique
1. Oral Intubation
Oral intubation is often the preferred method in emergency situations and when nasal intubation is contraindicated. Indications include:
- Emergent Intubation: Situations such as cardiopulmonary resuscitation (CPR), unconsciousness, or apnea.
- Oral or Mandibular Trauma: When there is significant trauma to the oral cavity or mandible that may complicate nasal access.
- Cervical Spine Conditions: Conditions such as ankylosis, arthritis, or trauma that may limit neck movement.
- Gagging and Vomiting: In patients who are unable to protect their airway due to these conditions.
- Agitation: In cases where the patient is agitated and requires sedation and airway protection.
2. Nasal Intubation
Nasal intubation is indicated in specific situations where oral intubation may be difficult or impossible. Indications include:
- Nasal Obstruction: When there is a blockage in the oral route.
- Paranasal Disease: Conditions affecting the nasal passages that may necessitate nasal access.
- Awake Intubation: In cases where the patient is cooperative and can tolerate the procedure.
- Short (Bull) Neck: In patients with anatomical challenges that make oral intubation difficult.
3. Tracheostomy
Tracheostomy is indicated for long-term airway management or when other methods are not feasible. Indications include:
- Inability to Insert Translational Tube: When oral or nasal intubation fails or is not possible.
- Need for Long-Term Definitive Airway: In patients requiring prolonged mechanical ventilation or airway support.
- Obstruction Above Cricoid Cartilage: Conditions that obstruct the airway at or above the cricoid level.
- Complications of Translational Intubation: Such as glottic incompetence or inability to clear tracheobronchial secretions.
- Sleep Apnea Unresponsive to CPAP: In patients with severe obstructive sleep apnea who do not respond to continuous positive airway pressure (CPAP) therapy.
- Facial or Laryngeal Trauma: Structural contraindications to translaryngeal intubation.
Contraindications for Nasal Intubation
- Severe Fractures of the Midface: Nasal intubation is contraindicated due to the risk of further injury and complications.
- Nasal Fractures: Similar to midface fractures, nasal fractures can complicate nasal intubation and increase the risk of injury.
- Basilar Skull Fractures: The risk of entering the cranial cavity or causing cerebrospinal fluid (CSF) leaks makes nasal intubation unsafe in these cases.
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Contraindications for Oral Intubation
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Severe Facial or Oral Trauma:
- Significant injuries to the face, jaw, or oral cavity may make oral intubation difficult or impossible and increase the risk of further injury.
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Obstruction of the Oral Cavity:
- Conditions such as large tumors, severe swelling, or foreign bodies that obstruct the oral cavity can prevent successful intubation.
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Cervical Spine Instability:
- Patients with unstable cervical spine injuries may be at risk of further injury if neck extension is required for intubation.
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Severe Maxillofacial Deformities:
- Anatomical abnormalities that prevent proper visualization of the airway or access to the trachea.
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Inability to Open the Mouth:
- Conditions such as trismus (lockjaw) or severe oral infections that limit mouth opening can hinder intubation.
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Severe Coagulopathy:
- Patients with bleeding disorders may be at increased risk of bleeding during the procedure.
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Anticipated Difficult Airway:
- In cases where the airway is expected to be difficult to manage, alternative methods may be preferred.
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Contraindications for Tracheostomy
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Severe Coagulopathy:
- Patients with significant bleeding disorders may be at risk for excessive bleeding during the procedure.
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Infection at the Site of Incision:
- Active infections in the neck or tracheostomy site can increase the risk of complications and should be addressed before proceeding.
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Anatomical Abnormalities:
- Significant anatomical variations or deformities in the neck that may complicate the procedure or increase the risk of injury to surrounding structures.
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Severe Respiratory Distress:
- In some cases, if a patient is in severe respiratory distress, immediate intubation may be prioritized over tracheostomy.
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Patient Refusal:
- If the patient is conscious and refuses the procedure, it should not be performed unless there is an immediate life-threatening situation.
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Inability to Maintain Ventilation:
- If the patient cannot be adequately ventilated through other means, tracheostomy may be necessary, but it should be performed with caution.
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Unstable Hemodynamics:
- Patients with severe hemodynamic instability may not tolerate the procedure well, and alternative airway management strategies may be required.