NEET MDS Lessons
General Surgery
Dautrey Procedure
The Dautrey procedure is a surgical intervention aimed at preventing dislocation of the temporomandibular joint (TMJ) by creating a mechanical obstacle that restricts abnormal forward translation of the condylar head. This technique is particularly beneficial for patients who experience recurrent TMJ dislocations or subluxations, especially when conservative management strategies have proven ineffective.
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Indications:
- The Dautrey procedure is indicated for patients with a history of recurrent TMJ dislocations. It is particularly useful when conservative treatments, such as physical therapy or splint therapy, have failed to provide adequate stabilization of the joint.
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Surgical Technique:
- Osteotomy of the Zygomatic Arch: The procedure begins with an osteotomy, which involves surgically cutting the zygomatic arch, the bony structure that forms the prominence of the cheek.
- Depressing the Zygomatic Arch: After the osteotomy, the zygomatic arch is depressed in front of the condylar head. This depression creates a physical barrier that acts as an obstacle to the forward movement of the condylar head during jaw opening or excessive movement.
- Stabilization: The newly positioned zygomatic arch limits the range of motion of the condylar head, thereby reducing the risk of dislocation during functional activities such as chewing or speaking.
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Mechanism of Action:
- By altering the position of the zygomatic arch, the Dautrey procedure effectively changes the biomechanics of the TMJ. The new position of the zygomatic arch prevents the condylar head from translating too far forward, which is a common cause of dislocation.
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Postoperative Care:
- Following the procedure, patients may require a period of recovery
and rehabilitation. This may include:
- Dietary Modifications: Soft diet to minimize stress on the TMJ during the healing process.
- Pain Management: Use of analgesics to manage postoperative discomfort.
- Physical Therapy: Exercises to restore normal function and range of motion in the jaw.
- Following the procedure, patients may require a period of recovery
and rehabilitation. This may include:
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Outcomes:
- The Dautrey procedure has been shown to be effective in preventing recurrent TMJ dislocations. Patients often experience improved joint stability and a better quality of life following the surgery. Successful outcomes can lead to reduced pain, improved jaw function, and enhanced overall satisfaction with treatment.
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.
Inflammation is the respone of the body to an irritant.
Stages of Inflammation
1. General: Temperature Raised. In severe cases bacteremia or septicemia ,rigors may occur.
2. Local: classical signs of inflammation are due to hyperemia and inflammation exudate
i) Heat: inflammed area feels warmer than the surrounding tissues.
ii) Redness
iii) Tenderness: Due to pressure of exudate on the surrounding nerves If the exudate is under tension, e.g. a furuncle (boil) of the ear, pain is severe.
iv) swelling
v) Loss of function.
The termination of Inflammation
This may be by:1. Resolution 2. Suppuration 3. Ulceration 4. Ganangren s. Fibrosis
Management
i. Increase the patients resistance., Rest, Relief of pain by analgesics, Diet: High protein and high calorie diet with vitamins, Antibiotics, Prevent further contamination of wound.
Surgical measures
1. Excision: If possible as in appendicectomy.
2. Incision and drainage: If an abscess forms.
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.
SHOCK
Shock is defined as a pathological state causing inadequate oxygen delivery to the peripheral tissues and resulting in lactic acidosis, cellular hypoxia and disruption of normal metabolic condition.
CLASSIFICATION
Shock is generally classified into three major categories:
1. Hypovolemic shock
2. Cardiogenic shock
3. Distributive shock
Distributive shock is further subdivided into three subgroups:
a. Septic shock
b. Neurogenic shock
c. Anaphylactic shock
Hypovolemic shock is present when marked reduction in oxygen delivery results from diminished cardiac output secondary to inadequate vascular volume. In general, it results from loss of fluid from circulation, either directly or indirectly.
e.g. ? Hemorrhage
• Loss of plasma due to burns
• Loss of water and electrolytes in diarrhea
• Third space loss (Internal fluid shift into inflammatory exudates in
the peritoneum, such as in pancreatitis.)
Cardiogenic shock is present when there is severe reduction in oxygen delivery secondary to impaired cardiac function. Usually it is due to myocardial infarction or pericardial tamponade.
Septic Shock (vasogenic shock) develops as a result of the systemic effect of infection. It is the result of a septicemia with endotoxin and exotoxin release by gram-negative and gram-positive bacteria. Despite normal or increased cardiac output and oxygen delivery, cellular oxygen consumption is less than normal due to impaired extraction as a result of impaired metabolism.
Neurogenic shock results primarily from the disruption of the sympathetic nervous system which may be due to pain or loss of sympathetic tone, as in spinal cord injuries.
PATHO PHYSIOLOGY OF SHOCK
Shock stimulates a physiologic response. This circulatory response to hypotension is to conserve perfusion to the vital organs (heart and brain) at the expense of other tissues. Progressive vasoconstriction of skin, splanchnic and renal vessels leads to renal cortical necrosis and acute renal failure. If not corrected in time, shock leads to organ failure and sets up a vicious circle with hypoxia and acidosis.
CLINICAL FEATURES
The clinical presentation varies according to the cause. But in general patients with hypotension and reduced tissue perfusion presents with:
• Tachycardia
• Feeble pulse
• Narrow pulse pressure
• Cold extremities (except septic shock)
• Sweating, anxiety
• Breathlessness / Hyperventilation
• Confusion leading to unconscious state
PATHO PHYSIOLOGY OF SHOCK
Shock stimulates a physiologic response. This circulatory response to hypotension is to conserve perfusion to the vital organs (heart and brain) at the expense of other tissues. Progressive vasoconstriction of skin, splanchnic and renal vessels leads to renal cortical necrosis and acute renal failure. If not corrected in time, shock leads to organ failure and sets up a vicious circle with hypoxia and acidosis.
CLINICAL FEATURES
The clinical presentation varies according to the cause. But in general patients with hypotension and reduced tissue perfusion presents with:
• Tachycardia
• Feeble pulse
• Narrow pulse pressure
• Cold extremities (except septic shock)
• Sweating, anxiety
• Breathlessness / Hyperventilation
• Confusion leading to unconscious state
An ulcer is a break in the continuity of the skin or the mucous membrane.
Mode of onset: Traumatic ulcers heal when the traumatic agent is removed., If it persists it becomes chronic as in the case of dental ulcer of the tongue. Ulcers may develop spontaneously as in the case of gumma (syphilitic ulcer). It may develop with varicose veins called varicose ulcer, which develops in the lower third of the leg.
Sometimes a malignant ulcer develops in a scar called Marjolin’s ulcer. Special features are:
No pain - as there are no nerves. It does not spread - as there is scar tissue. No metastases - as there are no lymphatics Treatment:- Wide excision.
Classification of Ulcer
A) Pathologically
I. Non-specific ulcers:
a. Due to infected wound after trauma, that is physical or chemical agents.
b. Due to local infection example dental ulcer, pressure sore
Specific ulcers: Caused by specific infection
a. Syphilitic ulcers (Hunterian chancre)
b. Tubercular ulcers, actinomycosis
Trophic ulcer:- Caused by two factors:
Diminished nutrition due to inadequate blood supply to the tissues
Eg. Ulcers in Buerger’s Disease, Artherosclerosis
b. Diminished or absence of sensation of the skin leading to perforating ulcer of the foot
iv. Malignant ulcer: Due to squamous cell carcinoma, rodent ulcers and melanoma.
B) Clinical classification of ulcers
1. Acute Ulcer: The edge is inflamed oedematous and painful with slough in the floor and n o granulation tissue. Profuse purulent Discgarge seen
2. Healing ulcers: edge sloping with bluish margin The floor is covered with a red, healthy granulation tissue.
3. Chronic or callous ulcer (non- healing) There is no tendency to heal by itself, the base is jndurated unhealthy granulation tissue is present in the floor The edge is rounded and thickened.
Chronic ulcer occur due to:
Chronic infection , Defective circulation , Foreign body, Persistent local oedema , Malignancy , Diabetes , Malnutrition (loss of proteins), Gout
Specific Ulcers
Tubeculous Ulcer
Edge Undermined, floor contains granulation tissue a watery discharge is present. Caseous material is found in the floor of the ulcer. It usually occurs in tubercular lymphadenitis in the neck, axilla or groin.
Syphilitic Ulcer
a) Huntarian Chancre or primary sore or hard chancre: usuaIly occurs over the genitalia especially on penis. Occurs in the primary stage of syphilis Ulcer is round or oval, it is hard,indurated, elevated and painless It feels like a button, discharges serum containing spirochetes (cork screw) which is highly infective.
b) In the Secondary stage mucous patches and condylomata occurs The ulcers are shallow white patches, of sodden thickness which occur in the mouth and tongue. Condyloma are hypertrophied epithelium with serous discharge occurring in mucocutaneous junction around the anus. The regional lymphnod (inguinal transverse chain) are enlarged.
c) In tertiary stage of syphilis gummatous ulcers occur They have a punched out edge and wash Ieather floor. They occur on the subcutaneous bones like sternum and tibia. They are painless and refuse to heal.
Soft Sore (chanchroid)
They are painful muitiple ulcers, with copious discharge. They are caused by Bacillus Ducrey lncubation time is 3 to 4 days. located on glans penis and prepuce is due to venereal infection. They are associated with enlarged called bilateral inguinal lymphnodes
Tropical ulcer:
a) Oriental Sore - due to L. Tropica (lieshmaniasis)
b) Ulcers and sinuses are due to guinea worm abscess
c) Histoplasmosis with multiple ulcers on the tibia.
d) Chronic ulcers due to yaws
e) Amoebic ulcers occur in colon_and rectum , flask shaped ulcers , undermined edge , caused by Entamoeba Histolytica
Varicose Ulcer:
Associated with varicose veins. Occurs on the inner aspect of the lower third of leg , chronic ulcer The surrounding area is pigmented and eczema is present. The sore is longitudinally oval It does not penetrate the deep fascia and is painless The base is adherent to the periosteum of the tibia
Rodent ulcer
Usually Occurs on the face above a line joining the lobule of the ear to the angle of the mouth. Usually occurs at the inner canthous of the eye . Edge is raised and rolled, Erodes the deeper structures and the bone, the lyrnph nodes are not involved.
Treatment: If small wide excision is done with skin grafting, If large, radiotherapy is given.
Malignant Ulcer
Occurs due to chronic irritation as in the case of malignant ulcer of the tongue. The edge is everted. The floor is covered with slough and tumor tissue The regional lymph nodes are hard.
Initially mobile later becomes hard
Treatment: Wide excision is done.
Marjolin ulcer: Malignant Ulcer occurring on scar of Burns
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