Transoral Lithotomy: Procedure for Submandibular Duct Stone Removal

Transoral lithotomy is a surgical technique used to remove stones (calculi) from the submandibular duct (Wharton's duct). This procedure is typically performed under local anesthesia and is effective for addressing sialolithiasis (the presence of stones in the salivary glands).

Procedure

1. Preoperative Preparation:

   • Radiographic Assessment: The exact location of the stone is determined using imaging studies, such as X-rays or ultrasound, to guide the surgical approach.
   • Local Anesthesia: The procedure is performed under local anesthesia to minimize discomfort for the patient.

2. Surgical Technique:

   • Suture Placement: A suture is placed behind the stone to prevent it from moving backward during the procedure, facilitating easier access.
   • Incision: An incision is made in the mucosa of the floor of the mouth, parallel to the duct. Care is taken to avoid injury to surrounding structures, including:
     • Lingual Nerve: Responsible for sensory innervation to the tongue.
     • Submandibular Gland: The gland itself should be preserved to maintain salivary function.

3. Blunt Dissection:

   • After making the incision, blunt dissection is performed to carefully displace the surrounding tissue and expose the duct.

4. Identifying the Duct:

   • The submandibular duct is located, and the segment of the duct that contains the stone is identified.

5. Stone Removal:

   • A longitudinal incision is made over the stone within the duct. The stone is then extracted using small forceps. Care is taken to ensure complete removal to prevent recurrence.

6. Postoperative Considerations:

   • After the stone is removed, the incision may be closed with sutures, and the area is monitored for any signs of complications.

Complications

• Bacterial Sialadenitis: If there is a secondary infection following the procedure, it can lead to bacterial sialadenitis, which is an inflammation of the salivary gland due to infection. Symptoms may include pain, swelling, and purulent discharge from the duct.

Airway Management in Medical Emergencies: Tracheostomy and Cricothyrotomy

1. Establishing a Patent Airway

• Immediate Goal: The primary objective in any emergency involving airway obstruction is to ensure that the patient has a clear and patent airway to facilitate breathing.
• Procedures Available: Various techniques exist to achieve this, ranging from nonsurgical methods to surgical interventions.

2. Surgical Interventions

A. Tracheostomy

• A tracheostomy is a surgical procedure that involves creating an opening in the trachea (windpipe) through the neck to establish an airway.
• Indications:
  • Prolonged mechanical ventilation.
  • Severe upper airway obstruction (e.g., due to tumors, trauma, or swelling).
  • Need for airway protection in patients with impaired consciousness or neuromuscular disorders.
• Procedure:
  • An incision is made in the skin over the trachea, A tracheostomy incision is made between the second and third tracheal rings, which is below the larynx. The incision is usually 2–3 cm long and can be vertical or horizontaland the trachea is then opened to insert a tracheostomy tube.
  • This procedure requires considerable knowledge of anatomy and technical skill to perform safely and effectively.

B. Cricothyrotomy

• Definition: A cricothyrotomy is a surgical procedure that involves making an incision through the skin over the cricothyroid membrane (located between the thyroid and cricoid cartilages) to establish an airway.
• Indications:
  • Emergency situations where rapid access to the airway is required, especially when intubation is not possible.
  • Situations where facial or neck trauma makes traditional intubation difficult.
• Procedure:
  • A vertical incision is made over the cricothyroid membrane, and a tube is inserted directly into the trachea.
  • This procedure is typically quicker and easier to perform than a tracheostomy, making it suitable for emergency situations.

3. Nonsurgical Techniques for Airway Management

A. Abdominal Thrust (Heimlich Maneuver)

•  The Heimlich maneuver is a lifesaving technique used to relieve choking caused by a foreign body obstructing the airway.
• Technique:
  • The rescuer stands behind the patient and wraps their arms around the patient's waist.
  • A fist is placed just above the navel, and quick, inward and upward thrusts are applied to create pressure in the abdomen, which can help expel the foreign object.
• Indications: This technique is the first-line approach for conscious patients experiencing airway obstruction.

B. Back Blows and Chest Thrusts

• Back Blows:
  • The rescuer delivers firm blows to the back between the shoulder blades using the heel of the hand. This can help dislodge an object obstructing the airway.
• Chest Thrusts:
  • For patients who are obese or pregnant, chest thrusts may be more effective. The rescuer stands behind the patient and performs thrusts to the chest, similar to the Heimlich maneuver.

Structure of Orbital Walls

The orbit is a complex bony structure that houses the eye and its associated structures. It is composed of several walls, each with distinct anatomical features and clinical significance. Here’s a detailed overview of the structure of the orbital walls:

1. Lateral Wall

• Composition: The lateral wall of the orbit is primarily formed by two bones:
  • Zygomatic Bone: This bone contributes significantly to the lateral aspect of the orbit.
  • Greater Wing of the Sphenoid: This bone provides strength and stability to the lateral wall.
• Orientation: The lateral wall is inclined at approximately 45 degrees to the long axis of the skull, which is important for the positioning of the eye and the alignment of the visual axis.

2. Medial Wall

• Composition: The medial wall is markedly different from the lateral wall and is primarily formed by:
  • Orbital Plate of the Ethmoid Bone: This plate is very thin and fragile, making the medial wall susceptible to injury.
• Height and Orientation: The medial wall is about half the height of the lateral wall. It is aligned parallel to the antero-posterior axis (median plane) of the skull and meets the floor of the orbit at an angle of about 45 degrees.
• Fragility: The medial wall is extremely fragile due to its proximity to:
  • Ethmoid Air Cells: These air-filled spaces can compromise the integrity of the medial wall.
  • Nasal Cavity: The close relationship with the nasal cavity further increases the risk of injury.

3. Roof of the Orbit

• Composition: The roof is formed by the frontal bone and is reinforced laterally by the greater wing of the sphenoid.
• Thickness: While the roof is thin, it is structurally reinforced, which helps protect the contents of the orbit.
• Fracture Patterns: Fractures of the roof often involve the frontal bone and tend to extend medially. Such fractures can lead to complications, including orbital hemorrhage or involvement of the frontal sinus.

4. Floor of the Orbit

• Composition: The floor is primarily formed by the maxilla, with contributions from the zygomatic and palatine bones.
• Thickness: The floor is very thin, typically measuring about 0.5 mm in thickness, making it particularly vulnerable to fractures.
• Clinical Significance:
  • Blow-Out Fractures: The floor is commonly involved in "blow-out" fractures, which occur when a blunt force impacts the eye, causing the floor to fracture and displace. These fractures can be classified as:
    • Pure Blow-Out Fractures: Isolated fractures of the orbital floor.
    • Impure Blow-Out Fractures: Associated with fractures in the zygomatic area.
  • Infraorbital Groove and Canal: The presence of the infraorbital groove and canal further weakens the floor. The infraorbital nerve and vessels run through this canal, making them susceptible to injury during fractures. Compression, contusion, or direct penetration from bone spicules can lead to sensory deficits in the distribution of the infraorbital nerve.

Nasogastric Tube (Ryles Tube)

A 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

Lateral Pharyngeal Space

The lateral pharyngeal space is an important anatomical area in the neck that plays a significant role in various clinical conditions, particularly infections. Here’s a detailed overview of its anatomy, divisions, clinical significance, and potential complications.

Anatomy

• Shape and Location: The lateral pharyngeal space is a potential cone-shaped space or cleft.
  • Base: The base of the cone is located at the base of the skull.
  • Apex: The apex extends down to the greater horn of the hyoid bone.
• Divisions: The space is divided into two compartments by the styloid process:
  • Anterior Compartment: Located in front of the styloid process.
  • Posterior Compartment: Located behind the styloid process.

Boundaries

• Medial Boundary: The lateral wall of the pharynx.
• Lateral Boundary: The medial surface of the mandible and the muscles of the neck.
• Superior Boundary: The base of the skull.
• Inferior Boundary: The greater horn of the hyoid bone.

Contents

The lateral pharyngeal space contains various important structures, including:

• Muscles: The stylopharyngeus and the superior pharyngeal constrictor muscles.
• Nerves: The glossopharyngeal nerve (CN IX) and the vagus nerve (CN X) may be present in this space.
• Vessels: The internal carotid artery and the internal jugular vein are closely associated with this space, particularly within the carotid sheath.

Clinical Significance

• Infection Risk: Infection in the lateral pharyngeal space can be extremely serious due to its proximity to vital structures, particularly the carotid sheath, which contains the internal carotid artery, internal jugular vein, and cranial nerves.

• Potential Complications:

  • Spread of Infection: Infections can spread from the lateral pharyngeal space to other areas, including the mediastinum, leading to life-threatening conditions such as mediastinitis.
  • Airway Compromise: Swelling or abscess formation in this space can lead to airway obstruction, necessitating urgent medical intervention.
  • Vascular Complications: The close relationship with the carotid sheath means that infections can potentially involve the carotid artery or jugular vein, leading to complications such as thrombosis or carotid artery rupture.

Diagnosis and Management

• Diagnosis:

  • Clinical examination may reveal signs of infection, such as fever, neck swelling, and difficulty swallowing.
  • Imaging studies, such as CT scans, are often used to assess the extent of infection and involvement of surrounding structures.

• Management:

  • Antibiotics: Broad-spectrum intravenous antibiotics are typically initiated to manage the infection.
  • Surgical Intervention: In cases of abscess formation or significant swelling, surgical drainage may be necessary to relieve pressure and remove infected material.

Lines in Third Molar Assessment

In the context of third molar (wisdom tooth) assessment and extraction, several lines are used to evaluate the position and inclination of the tooth, as well as the amount of bone that may need to be removed during extraction. These lines provide valuable information for planning the surgical approach and predicting the difficulty of the extraction.

1. White Line

• Description: The white line is a visual marker that runs over the occlusal surfaces of the first, second, and third molars.
• Purpose: This line serves as an indicator of the axial inclination of the third molar. By assessing the position of the white line, clinicians can determine the orientation of the third molar in relation to the adjacent teeth and the overall dental arch.
• Clinical Relevance: The inclination of the third molar can influence the complexity of the extraction procedure, as well as the potential for complications.

2. Amber Line

• Description: The amber line is drawn from the bone distal to the third molar towards the interceptal bone between the first and second molars.
• Purpose: This line helps to delineate which parts of the third molar are covered by bone and which parts are not. Specifically:
  • Above the Amber Line: Any part of the tooth above this line is not covered by bone.
  • Below the Amber Line: Any part of the tooth below this line is covered by bone.
• Clinical Relevance: The amber line is particularly useful in the Pell and Gregory classification, which categorizes the position of the third molar based on its relationship to the surrounding structures and the amount of bone covering it.

3. Red Line (George Winter's Third Line)

• Description: The red line is a perpendicular line drawn from the amber line to an imaginary line of application of an elevator. This imaginary line is positioned at the cement-enamel junction (CEJ) on the mesial aspect of the tooth, except in cases of disto-angular impaction, where it is at the distal CEJ.
• Purpose: The red line indicates the amount of bone that must be removed before the elevation of the tooth can occur. It effectively represents the depth of the tooth in the bone.
• Clinical Relevance: The length of the red line correlates with the difficulty of the extraction:
  • Longer Red Line: Indicates that more bone needs to be removed, suggesting a more difficult extraction.
  • Shorter Red Line: Suggests that less bone removal is necessary, indicating an easier extraction.