NEET MDS Lessons
General Surgery
Suture Materials
Sutures are essential in surgical procedures for wound closure and tissue approximation. Various types of sutures are available, each with unique properties, advantages, and applications. Below is a summary of some commonly used suture materials, including chromic catgut, polypropylene, polyglycolic acid, and polyamide (nylon).
1. Chromic Catgut
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Description:
- Chromic catgut is a natural absorbable suture made from collagen derived from the submucosa of sheep intestines or the serosa of beef cattle intestines. It is over 99% pure collagen.
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Absorption Process:
- The absorption of chromic catgut occurs through enzymatic digestion by proteolytic enzymes, which are derived from lysozymes contained within polymorphonuclear leukocytes (polymorphs) and macrophages.
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Absorption Rate:
- The absorption rate depends on the size of the suture and whether it is plain or chromicized. Typically, absorption is completed within 60-120 days.
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Applications:
- Commonly used in soft tissue approximation and ligation, particularly in areas where a temporary support is needed.
2. Polypropylene (Proline)
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Description:
- Polypropylene is a synthetic monofilament suture made from a purified and dyed polymer.
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Properties:
- It has an extremely high tensile strength, which it retains indefinitely after implantation. Polypropylene is non-biodegradable, meaning it does not break down in the body.
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Applications:
- Ideal for use in situations where long-term support is required, such as in vascular surgery, hernia repairs, and other procedures where permanent sutures are beneficial.
3. Polyglycolic Acid
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Description:
- Polyglycolic acid is a synthetic absorbable suture formed by linking glycolic acid monomers to create a polymer.
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Properties:
- It is known for its predictable absorption rate and is commonly used in various surgical applications.
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Applications:
- Frequently used in soft tissue approximation, including in gastrointestinal and gynecological surgeries, where absorbable sutures are preferred.
4. Polyamide (Nylon)
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Description:
- Polyamide, commonly known as nylon, is a synthetic non-absorbable suture that is chemically extruded and generally available in monofilament form.
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Properties:
- Nylon sutures have a low coefficient of friction, making passage through tissue easy. They also elicit minimal tissue reaction.
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Applications:
- Used in a variety of surgical procedures, including skin closure, where a strong, durable suture is required.
Advanced Trauma Life Support (ATLS)
Introduction
Trauma is a leading cause of death, particularly in the first four decades of life, and ranks as the third most common cause of death overall. The Advanced Trauma Life Support (ATLS) program was developed to provide a systematic approach to the management of trauma patients, ensuring that life-threatening conditions are identified and treated promptly.
Mechanisms of Injury
In trauma, injuries can be classified based on their mechanisms:
Overt Mechanisms
- Penetrating Trauma: Injuries caused by objects that penetrate the skin and underlying tissues.
- Blunt Trauma: Injuries resulting from impact without penetration, such as collisions or falls.
- Thermal Trauma: Injuries caused by heat, including burns.
- Blast Injury: Injuries resulting from explosions, which can cause a combination of blunt and penetrating injuries.
Covert Mechanisms
- Blunt Trauma: Often results in internal injuries that may not be immediately apparent.
- Penetrating Trauma: Can include knife wounds and other sharp objects.
- Penetrating Knife: Specific injuries from stabbing.
- Gunshot Injury: Injuries caused by firearms, which can have extensive internal damage.
The track of penetrating injuries can often be identified by the anatomy involved, helping to determine which organs may be injured.
Steps in ATLS
The ATLS protocol consists of a systematic approach to trauma management, divided into two main surveys:
1. Primary Survey
- Objective: Identify and treat life-threatening conditions.
- Components:
- A - Airway: Ensure the airway is patent. In patients with a Glasgow Coma Scale (GCS) of 8 or less, immediate intubation is necessary. Maintain cervical spine stability.
- B - Breathing: Assess ventilation and oxygenation. Administer high-flow oxygen via a reservoir mask. Identify and treat conditions such as tension pneumothorax, flail chest, massive hemothorax, and open pneumothorax.
- C - Circulation: Evaluate circulation based on:
- Conscious level (indicates cerebral perfusion)
- Skin color
- Rapid, thready pulse (more reliable than blood pressure)
- D - Disability: Assess neurological status using the Glasgow Coma Scale (GCS).
- E - Exposure: Fully expose the patient to assess for injuries on the front and back.
2. Secondary Survey
- Objective: Conduct a thorough head-to-toe examination to identify all injuries.
- Components:
- AMPLE: A mnemonic to gather important patient
history:
- A - Allergy: Any known allergies.
- M - Medications: Current medications the patient is taking.
- P - Past Medical History: Relevant medical history.
- L - Last Meal: When the patient last ate.
- E - Events of Incident: Details about the mechanism of injury.
- AMPLE: A mnemonic to gather important patient
history:
Triage
Triage is the process of sorting patients based on the severity of their condition. The term "triage" comes from the French word meaning "to sort." In trauma settings, patients are categorized using a color-coded system:
- Red: First priority (critical patients, e.g., tension pneumothorax).
- Yellow: Second priority (urgent cases, e.g., pelvic fracture).
- Green: Third priority (minor injuries, e.g., simple fracture).
- Black: Zero priority (patients who are dead or unsalvageable).
Blunt Trauma
- Common Causes: The most frequent cause of blunt trauma is road traffic accidents.
- Seat Belt Use: Wearing seat belts significantly reduces
mortality rates:
- Front row occupants: 45% reduction in death rate.
- Rear seat belt use: 80% reduction in death rate for front seat occupants.
- Seat Belt Injuries: Marks on the thorax indicate a fourfold increase in thoracic injuries, while abdominal marks indicate a threefold increase in abdominal injuries.
Radiographs in Trauma
Key radiographic views to obtain in trauma cases include:
- Lateral cervical spine
- Anteroposterior chest
- Anteroposterior pelvis
Ludwig's Angina
Ludwig's angina is a serious, potentially life-threatening cellulitis or connective tissue infection of the submandibular space. It typically arises from infections of the teeth, particularly the second or third molars, and can lead to airway obstruction due to swelling. This condition is named after the German physician Wilhelm Friedrich von Ludwig, who first described it in the 19th century.
Etiology
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Common Causes:
- Dental infections (especially from the lower molars)
- Infections from the floor of the mouth
- Trauma to the submandibular area
- Occasionally, infections can arise from other sources, such as the oropharynx or skin.
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Microbial Agents:
- Mixed flora, including both aerobic and anaerobic bacteria.
- Common organisms include Streptococcus, Staphylococcus, and Bacteroides species.
Pathophysiology
- The infection typically begins in the submandibular space and can spread rapidly due to the loose connective tissue in this area.
- The swelling can lead to displacement of the tongue and can obstruct the airway, making it a medical emergency.
Clinical Presentation
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Symptoms:
- Swelling of the submandibular area, which may be bilateral
- "Brawny induration" (firm, non-fluctuant swelling)
- Pain and tenderness in the submandibular region
- Difficulty swallowing (dysphagia) and speaking (dysarthria)
- Fever and malaise
- Possible elevation of the floor of the mouth and displacement of the tongue
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Signs:
- Swelling may extend to the neck and may cause "bull neck" appearance.
- Trismus (limited mouth opening) may be present.
- Respiratory distress due to airway compromise.
Diagnosis
- Clinical Evaluation: Diagnosis is primarily clinical based on history and physical examination.
- Imaging:
- CT scan of the neck may be used to assess the extent of the infection and to rule out other conditions.
- X-rays may show air in the soft tissues if there is a necrotizing infection.
Management
Initial Management
- Airway Management:
- Ensure the airway is patent; this may require intubation or tracheostomy in severe cases.
Medical Treatment
- Antibiotics:
- Broad-spectrum intravenous antibiotics are initiated to cover both
aerobic and anaerobic bacteria. Common regimens may include:
- Ampicillin-sulbactam
- Clindamycin
- Metronidazole combined with a penicillin derivative
- Broad-spectrum intravenous antibiotics are initiated to cover both
aerobic and anaerobic bacteria. Common regimens may include:
Surgical Intervention
- Drainage:
- Surgical drainage may be necessary if there is an abscess formation or significant swelling.
- Incisions are typically made in the submandibular area to allow for drainage of pus and to relieve pressure.
Complications
- Airway Obstruction: The most critical complication, requiring immediate intervention.
- Sepsis: Can occur if the infection spreads systemically.
- Necrotizing fasciitis: Rare but serious complication that may require extensive surgical intervention.
- Thrombosis of the internal jugular vein: Can occur due to the spread of infection.
Prognosis
- With prompt diagnosis and treatment, the prognosis is generally good. However, delays in management can lead to significant morbidity and mortality due to airway compromise and systemic infection.