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General Surgery - NEETMDS- courses
NEET MDS Lessons
General Surgery

Types of Head Injury

1. Extradural Hematoma (EDH)

Overview

  • Demographics: Most common in young male patients.
  • Association: Always associated with skull fractures.
  • Injured Vessel: Middle meningeal artery.
  • Common Site of Injury: Temporal bone at the pterion (the thinnest part of the skull), which overlies the middle meningeal artery.
  • Location of Hematoma: Between the bone and the dura mater.

Other Common Sites

  1. Frontal fossa
  2. Posterior fossa
  3. May occur following disruption of major dural venous sinus.

Classical Presentation

  • Initial Injury: Followed by a lucid interval where the patient may only complain of a headache.
  • Deterioration: After minutes to hours, rapid deterioration occurs, leading to:
    • Contralateral hemiparesis
    • Reduced consciousness level
    • Ipsilateral pupillary dilatation (due to herniation)

Imaging

  • CT Scan: Shows a lentiform (lens-shaped or biconvex) hyperdense lesion between the brain and skull.

Treatment

  • Surgical Intervention: Immediate surgical evacuation via craniotomy.
  • Mortality Rate: Overall mortality is 18% for all cases of EDH, but only 2% for isolated EDH.

2. Acute Subdural Hematoma (ASDH)

Overview

  • Location: Accumulates in the space between the dura and arachnoid.
  • Injury Mechanism: Associated with cortical vessel disruption and brain laceration.
  • Primary Brain Injury: Often associated with primary brain injury.

Presentation

  • Consciousness: Impaired consciousness from the time of impact.

Imaging

  • CT Scan: Appears hyperdense, with hematoma spreading diffusely and having a concavo-convex appearance.

Treatment

  • Surgical Intervention: Evacuation via craniotomy.
  • Mortality Rate: Approximately 40%.

3. Chronic Subdural Hematoma (CSDH)

Overview

  • Demographics: Most common in patients on anticoagulants and antiplatelet agents.
  • History: Often follows a minor head injury weeks to months prior.
  • Pathology: Due to the tear of bridging veins leading to ASDH, which is clinically silent. As the hematoma breaks down, it increases in volume, causing mass effect on the underlying brain.

Clinical Features

  • Symptoms may include:
    • Headache
    • Cognitive decline
    • Focal neurological deficits (FND)
    • Seizures
  • Important to exclude endocrine, hypoxic, and metabolic causes in this group.

Imaging

  • CT Scan Appearance:
    • Acute blood (0–10 days): Hyperdense
    • Subacute blood (10 days to 2 weeks): Isodense
    • Chronic (> 2 weeks): Hypodense

Treatment

  • Surgical Intervention: Bur hole evacuation rather than craniotomy.
  • Anesthesia: Elderly patients can often undergo surgery under local anesthesia, despite comorbidities.

4. Subarachnoid Hemorrhage (SAH)

Overview

  • Causes: Most commonly due to aneurysms for spontaneous SAH, but trauma is the most common cause overall.
  • Management: Conservative treatment is often employed for trauma cases.

5. Cerebral Contusions

Overview

  • Definition: Bruising of the brain tissue due to trauma.
  • Mechanism: Often occurs at the site of impact (coup) and the opposite side (contrecoup).
  • Symptoms: Can range from mild confusion to severe neurological deficits depending on the extent of the injury.

Imaging

  • CT Scan: May show areas of low attenuation (hypodense) or high attenuation (hyperdense) depending on the age of the contusion.

Treatment

  • Management: Depends on the severity and associated injuries; may require surgical intervention if there is significant mass effect.

Excision of Lesions Involving the Jaw Bone

When excising lesions involving the jaw bone, various terminologies are used to describe the specific techniques and outcomes of the procedures.

1. Enucleation

  • Enucleation refers to the separation of a lesion from the bone while preserving bone continuity. This is achieved by removing the lesion along an apparent tissue or cleavage plane, which is often defined by an encapsulating or circumscribing connective tissue envelope derived from the lesion or surrounding bone.
  • Key Characteristics:
    • The lesion is contained within a defined envelope.
    • Bone continuity is maintained post-excision.

2. Curettage

  • Curettage involves the removal of a lesion from the bone by scraping, particularly when the lesion is friable or lacks an intact encapsulating tissue envelope. This technique may result in the removal of some surrounding bone.
  • Key Characteristics:
    • Indicates the inability to separate the lesion along a distinct tissue plane.
    • May involve an inexact or immeasurable thickness of surrounding bone.
    • If a measurable margin of bone is removed, it is termed "resection without continuity defect."

3. Marsupialization

  • Marsupialization is a surgical procedure that involves the exteriorization of a lesion by removing overlying tissue to expose its internal surface. This is done by excising a portion of the lesion bordering the oral cavity or another body cavity.
  • Key Characteristics:
    • Multicompartmented lesions are rendered unicompartmental.
    • The lesion is clinically cystic, and the excised tissue may include bone and/or overlying mucosa.

4. Resection Without Continuity Defect

  • This term describes the excision of a lesion along with a measurable perimeter of investing bone, without interrupting bone continuity. The anatomical relationship allows for the removal of the lesion while preserving the integrity of the bone.
  • Key Characteristics:
    • Bone continuity is maintained.
    • Adjacent soft tissue may be included in the resection.

5. Resection With Continuity Defect

  •  This involves the excision of a lesion that results in a defect in the continuity of the bone. This is often associated with more extensive resections.
  • Key Characteristics:
    • Bone continuity is interrupted.
    • May require reconstruction or other interventions to restore function.

6. Disarticulation

  •  Disarticulation is a special form of resection that involves the temporomandibular joint (TMJ) and results in a continuity defect.
  • Key Characteristics:
    • Involves the removal of the joint and associated structures.
    • Results in loss of continuity in the jaw structure.

7. Recontouring

  •  Recontouring refers to the surgical reduction of the size and/or shape of the surface of a bony lesion or bone part. The goal is to reshape the bone to conform to the adjacent normal bone surface or to achieve an aesthetic result.
  • Key Characteristics:
    • May involve lesions such as bone hyperplasia, torus, or exostosis.
    • Can be performed with or without complete eradication of the lesion (e.g., fibrous dysplasia).

Cricothyroidotomy

Cricothyroidotomy is a surgical procedure that involves making an incision through the skin over the cricothyroid membrane, which is located between the thyroid and cricoid cartilages in the neck. This procedure is performed to establish an emergency airway in situations where intubation is not possible or has failed, such as in cases of severe airway obstruction, facial trauma, or anaphylaxis.

Indications

Cricothyroidotomy is indicated in the following situations:

  • Acute Airway Obstruction: When there is a complete blockage of the upper airway due to swelling, foreign body, or trauma.
  • Failed Intubation: When attempts to secure an airway via endotracheal intubation have been unsuccessful.
  • Facial or Neck Trauma: In cases where traditional airway management is compromised due to injury.
  • Severe Anaphylaxis: When rapid airway access is needed and other methods are not feasible.

Anatomy

  • Cricothyroid Membrane: The membrane lies between the thyroid and cricoid cartilages and is a key landmark for the procedure.
  • Surrounding Structures: Important structures in the vicinity include the carotid arteries, jugular veins, and the recurrent laryngeal nerve, which must be avoided during the procedure.

Procedure

Preparation

  1. Positioning: The patient should be in a supine position with the neck extended to improve access to the cricothyroid membrane.
  2. Sterilization: The area should be cleaned and sterilized to reduce the risk of infection.
  3. Anesthesia: Local anesthesia may be administered, but in emergency situations, this step may be skipped.

Steps

  1. Identify the Cricothyroid Membrane: Palpate the thyroid and cricoid cartilages to locate the membrane, which is typically located about 1-2 cm below the thyroid notch.
  2. Make the Incision: Using a scalpel, make a vertical incision through the skin over the cricothyroid membrane, approximately 2-3 cm in length.
  3. Incise the Membrane: Carefully incise the cricothyroid membrane horizontally to create an opening into the airway.
  4. Insert the Airway Device:
    • A tracheostomy tube or a large-bore cannula (e.g., a 14-gauge catheter) is inserted into the opening to establish an airway.
    • Ensure that the device is positioned correctly to allow for ventilation.
  5. Secure the Airway: If using a tracheostomy tube, secure it in place to prevent dislodgment.

Post-Procedure Care

  • Ventilation: Connect the airway device to a bag-valve-mask (BVM) or ventilator to provide oxygenation and ventilation.
  • Monitoring: Continuously monitor the patient for signs of respiratory distress, oxygen saturation, and overall stability.
  • Consider Further Intervention: Plan for definitive airway management, such as a formal tracheostomy or endotracheal intubation, once the immediate crisis is resolved.

Complications

While cricothyroidotomy is a life-saving procedure, it can be associated with several complications, including:

  • Infection: Risk of infection at the incision site.
  • Hemorrhage: Potential bleeding from surrounding vessels.
  • Damage to Surrounding Structures: Injury to the recurrent laryngeal nerve, carotid arteries, or jugular veins.
  • Subcutaneous Emphysema: Air escaping into the subcutaneous tissue.
  • Tracheal Injury: If the incision is not made correctly, there is a risk of damaging the trachea.

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