NEET MDS Lessons
General Surgery
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.
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,
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
-
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.
-
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.
-
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.
-
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:
-
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.
-
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.
-
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.
-
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.
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
- Frontal fossa
- Posterior fossa
- 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.
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.
-
Contraindications for Oral Intubation
-
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.
-
Obstruction of the Oral Cavity:
- Conditions such as large tumors, severe swelling, or foreign bodies that obstruct the oral cavity can prevent successful intubation.
-
Cervical Spine Instability:
- Patients with unstable cervical spine injuries may be at risk of further injury if neck extension is required for intubation.
-
Severe Maxillofacial Deformities:
- Anatomical abnormalities that prevent proper visualization of the airway or access to the trachea.
-
Inability to Open the Mouth:
- Conditions such as trismus (lockjaw) or severe oral infections that limit mouth opening can hinder intubation.
-
Severe Coagulopathy:
- Patients with bleeding disorders may be at increased risk of bleeding during the procedure.
-
Anticipated Difficult Airway:
- In cases where the airway is expected to be difficult to manage, alternative methods may be preferred.
-
Contraindications for Tracheostomy
-
Severe Coagulopathy:
- Patients with significant bleeding disorders may be at risk for excessive bleeding during the procedure.
-
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.
-
Anatomical Abnormalities:
- Significant anatomical variations or deformities in the neck that may complicate the procedure or increase the risk of injury to surrounding structures.
-
Severe Respiratory Distress:
- In some cases, if a patient is in severe respiratory distress, immediate intubation may be prioritized over tracheostomy.
-
Patient Refusal:
- If the patient is conscious and refuses the procedure, it should not be performed unless there is an immediate life-threatening situation.
-
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.
-
Unstable Hemodynamics:
- Patients with severe hemodynamic instability may not tolerate the procedure well, and alternative airway management strategies may be required.
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
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
-
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.
-
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.
-
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.
-
Applications:
- Commonly used in soft tissue approximation and ligation, particularly in areas where a temporary support is needed.
2. Polypropylene (Proline)
-
Description:
- Polypropylene is a synthetic monofilament suture made from a purified and dyed polymer.
-
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.
-
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
-
Description:
- Polyglycolic acid is a synthetic absorbable suture formed by linking glycolic acid monomers to create a polymer.
-
Properties:
- It is known for its predictable absorption rate and is commonly used in various surgical applications.
-
Applications:
- Frequently used in soft tissue approximation, including in gastrointestinal and gynecological surgeries, where absorbable sutures are preferred.
4. Polyamide (Nylon)
-
Description:
- Polyamide, commonly known as nylon, is a synthetic non-absorbable suture that is chemically extruded and generally available in monofilament form.
-
Properties:
- Nylon sutures have a low coefficient of friction, making passage through tissue easy. They also elicit minimal tissue reaction.
-
Applications:
- Used in a variety of surgical procedures, including skin closure, where a strong, durable suture is required.