NEET MDS Lessons
Oral and Maxillofacial Surgery
Punch Biopsy Technique
A punch biopsy is a medical procedure used to obtain a small cylindrical sample of tissue from a lesion for diagnostic purposes. This technique is particularly useful for mucosal lesions located in areas that are difficult to access with conventional biopsy methods. Below is an overview of the punch biopsy technique, its applications, advantages, and potential limitations.
Punch Biopsy
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Procedure:
- A punch biopsy involves the use of a specialized instrument called a punch (a circular blade) that is used to remove a small, cylindrical section of tissue from the lesion.
- The punch is typically available in various diameters (commonly ranging from 2 mm to 8 mm) depending on the size of the lesion and the amount of tissue needed for analysis.
- The procedure is usually performed under local anesthesia to minimize discomfort for the patient.
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Technique:
- Preparation: The area around the lesion is cleaned and sterilized.
- Anesthesia: Local anesthetic is administered to numb the area.
- Punching: The punch is pressed down onto the lesion, and a twisting motion is applied to cut through the skin or mucosa, obtaining a tissue sample.
- Specimen Collection: The cylindrical tissue sample is then removed, and any bleeding is controlled.
- Closure: The site may be closed with sutures or left to heal by secondary intention, depending on the size of the biopsy and the location.
Applications
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Mucosal Lesions: Punch biopsies are particularly useful for obtaining samples from mucosal lesions in areas such as:
- Oral cavity (e.g., lesions on the tongue, buccal mucosa, or gingiva)
- Nasal cavity
- Anus
- Other inaccessible regions where traditional biopsy methods may be challenging.
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Skin Lesions: While primarily used for mucosal lesions, punch biopsies can also be performed on skin lesions to diagnose conditions such as:
- Skin cancers (e.g., melanoma, basal cell carcinoma)
- Inflammatory skin diseases (e.g., psoriasis, eczema)
Advantages
- Minimal Invasiveness: The punch biopsy technique is relatively quick and minimally invasive, making it suitable for outpatient settings.
- Preservation of Tissue Architecture: The cylindrical nature of the sample helps preserve the tissue architecture, which is important for accurate histopathological evaluation.
- Accessibility: It allows for sampling from difficult-to-reach areas that may not be accessible with other biopsy techniques.
Limitations
- Tissue Distortion: As noted, the punch biopsy technique can produce some degree of crushing or distortion of the tissues. This may affect the histological evaluation, particularly in delicate or small lesions.
- Sample Size: The size of the specimen obtained may be insufficient for certain diagnostic tests, especially if a larger sample is required for comprehensive analysis.
- Potential for Scarring: Depending on the size of the punch and the location, there may be a risk of scarring or changes in the appearance of the tissue after healing.
1. Radical Neck Dissection
- Complete removal of all ipsilateral
cervical lymph node groups (levels I-V) and three key non-lymphatic
structures:
- Internal jugular vein
- Sternocleidomastoid muscle
- Spinal accessory nerve
- Indication: Typically performed for extensive lymphatic involvement.
2. Modified Radical Neck Dissection
- Similar to radical neck dissection in terms
of lymph node removal (levels I-V) but with preservation of one or more of
the following structures:
- Type I: Preserves the spinal accessory nerve.
- Type II: Preserves the spinal accessory nerve and the sternocleidomastoid muscle.
- Type III: Preserves the spinal accessory nerve, sternocleidomastoid muscle, and internal jugular vein.
- Indication: Used when there is a need to reduce morbidity while still addressing lymphatic involvement.
3. Selective Neck Dissection
- Preservation of one or more lymph node groups that are typically removed in a radical neck dissection.
- Classification:
- Originally had named dissections (e.g., supraomohyoid neck dissection for levels I-III).
- The 2001 modification proposed naming dissections based on the cancer type and the specific node groups removed. For example, a selective neck dissection for oral cavity cancer might be referred to as a selective neck dissection (levels I-III).
- Indication: Used when there is a lower risk of lymphatic spread or when targeting specific areas.
4. Extended Neck Dissection
- Involves the removal of additional lymph
node groups or non-lymphatic structures beyond those included in a radical
neck dissection. This may include:
- Mediastinal nodes
- Non-lymphatic structures such as the carotid artery or hypoglossal nerve.
- Indication: Typically performed in cases of extensive disease or when there is a need to address additional areas of concern.
Glasgow Coma Scale (GCS): Best Verbal Response
The Glasgow Coma Scale (GCS) is a clinical scale used to assess a patient's level of consciousness and neurological function, particularly after a head injury. It evaluates three aspects: eye opening, verbal response, and motor response. The best verbal response (V) is one of the components of the GCS and is scored as follows:
Best Verbal Response (V)
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5 - Appropriate and Oriented:
- The patient is fully awake and can respond appropriately to questions, demonstrating awareness of their surroundings, time, and identity.
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4 - Confused Conversation:
- The patient is able to speak but is confused and disoriented. They may answer questions but with some level of confusion or incorrect information.
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3 - Inappropriate Words:
- The patient uses words but they are inappropriate or irrelevant to the context. The responses do not make sense in relation to the questions asked.
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2 - Incomprehensible Sounds:
- The patient makes sounds that are not recognizable as words. This may include moaning or groaning but does not involve coherent speech.
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1 - No Sounds:
- The patient does not make any verbal sounds or responses.
Differences between Cellulitis and Abscess
1. Duration
- Cellulitis: Typically presents in the acute phase, meaning it develops quickly, often within hours to days. It can arise from a break in the skin, such as a cut or insect bite, leading to a rapid inflammatory response.
- Abscess: Often represents a chronic phase of infection. An abscess may develop over time as the body attempts to contain an infection, leading to the formation of a localized pocket of pus.
2. Pain
- Cellulitis: The pain is usually severe and generalized, affecting a larger area of the skin and subcutaneous tissue. Patients may describe a feeling of tightness or swelling in the affected area.
- Abscess: Pain is localized to the site of the abscess and is often more intense. The pain may be throbbing and can worsen with movement or pressure on the area.
3. Localization
- Cellulitis: The infection has diffuse borders, meaning it spreads through the tissue without a clear boundary. This can make it difficult to determine the exact extent of the infection.
- Abscess: The infection is well-circumscribed, meaning it has a defined boundary. The body forms a capsule around the abscess, which helps to contain the infection.
4. Palpation
- Cellulitis: On examination, the affected area may feel doughy or indurated (hardened) due to swelling and inflammation. There is no distinct fluctuation, as there is no localized collection of pus.
- Abscess: When palpated, an abscess feels fluctuant, indicating the presence of pus. This fluctuation is a key clinical sign that helps differentiate an abscess from cellulitis.
5. Bacteria
- Cellulitis: Primarily caused by aerobic bacteria, such as Streptococcus and Staphylococcus species. These bacteria thrive in the presence of oxygen and are commonly found on the skin.
- Abscess: Often caused by anaerobic bacteria or a mixed flora, which can include both aerobic and anaerobic organisms. Anaerobic bacteria thrive in low-oxygen environments, which is typical in the center of an abscess.
6. Size
- Cellulitis: Generally larger in area, as it involves a broader region of tissue. The swelling can extend beyond the initial site of infection.
- Abscess: Typically smaller and localized to the area of the abscess. The size can vary, but it is usually confined to a specific area.
7. Presence of Pus
- Cellulitis: No pus is present; the infection is diffuse and does not form a localized collection of pus. The inflammatory response leads to swelling and redness but not to pus formation.
- Abscess: Yes, pus is present; the abscess is characterized by a collection of pus within a cavity. The pus is a result of the body’s immune response to the infection.
8. Degree of Seriousness
- Cellulitis: Generally considered more serious due to the potential for systemic spread and complications if untreated. It can lead to sepsis, especially in immunocompromised individuals.
- Abscess: While abscesses can also be serious, they are often more contained. They can usually be treated effectively with drainage, and the localized nature of the infection can make management more straightforward.
Clinical Significance
- Diagnosis: Differentiating between cellulitis and abscess is crucial for appropriate treatment. Cellulitis may require systemic antibiotics, while an abscess often requires drainage.
- Management:
- Cellulitis: Treatment typically involves antibiotics and monitoring for systemic symptoms. In severe cases, hospitalization may be necessary.
- Abscess: Treatment usually involves incision and drainage (I&D) to remove the pus, along with antibiotics if there is a risk of systemic infection.
Champy Technique of Fracture Stabilization
The Champy technique, developed by Champy et al. in the mid-1970s, is a method of fracture stabilization that utilizes non-compression monocortical miniplates applied as tension bands. This technique is particularly relevant in the context of mandibular fractures and is based on biomechanical principles that optimize the stability and healing of the bone.
Key Principles of the Champy Technique
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Biomechanical Considerations:
- Tensile and Compressive Stresses: Biomechanical studies have shown that tensile stresses occur in the upper border of the mandible, while compressive stresses are found in the lower border. This understanding is crucial for the placement of plates.
- Bending and Torsional Forces: The forces acting on the mandible primarily produce bending movements. In the symphysis and parasymphysis regions, torsional forces are more significant than bending moments.
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Ideal Osteosynthesis Line:
- Champy et al. established the "ideal osteosynthesis line" at the base of the alveolar process. This line is critical for the effective placement of plates to ensure stability during the healing process.
- Plate Placement:
- Anterior Region: In the area between the mental foramina, a subapical plate is placed, and an additional plate is positioned near the lower border of the mandible to counteract torsional forces.
- Posterior Region: Behind the mental foramen, the plate is applied just below the dental roots and above the inferior alveolar nerve.
- Angle of Mandible: The plate is placed on the broad surface of the external oblique ridge.
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Tension Band Principle:
- The use of miniplates as tension bands allows for the distribution of forces across the fracture site, enhancing stability and promoting healing.
Treatment Steps
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Reduction:
- The first step in fracture treatment is the accurate reduction of the fracture fragments to restore normal anatomy.
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Stabilization:
- Following reduction, stabilization is achieved using the Champy technique, which involves the application of miniplates in accordance with the biomechanical principles outlined above.
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Maxillomandibular Fixation (MMF):
- MMF is often used as a standard method for both reduction and stabilization, particularly in cases where additional support is needed.
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External Fixation:
- In cases of atrophic edentulous mandibular fractures, extensive soft tissue injuries, severe communication, or infected fractures, external fixation may be considered.
Classification of Internal Fixation Techniques
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Absolute Stability:
- Rigid internal fixation methods, such as compression plates, lag screws, and the tension band principle, fall under this category. These techniques provide strong stabilization but may compromise blood supply to the bone.
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Relative Stability:
- Techniques such as bridging, biologic (flexible) fixation, and the Champy technique are classified as relative stability methods. These techniques allow for some movement at the fracture site, which can promote healing by maintaining blood supply to the cortical bone.
Biologic Fixation
- New Paradigm:
- Biologic fixation represents a shift in fracture treatment philosophy, emphasizing that absolute stability is not always beneficial. Allowing for some movement at the fracture site can enhance blood supply and promote healing.
- Improved Blood Supply:
- Not pressing the plate against the bone helps maintain blood supply to the cortical bone and prevents the formation of early temporary porosity, which can be detrimental to healing.
Classification of Mandibular Fractures
Mandibular fractures are common injuries that can result from various causes, including trauma, accidents, and sports injuries. Understanding the classification and common sites of mandibular fractures is essential for effective diagnosis and management. Below is a detailed overview of the classification of mandibular fractures, focusing on the common sites and patterns of fracture.
General Overview
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Weak Points: The mandible has specific areas that are more susceptible to fractures due to their anatomical structure. The condylar neck is considered the weakest point and the most common site of mandibular fractures. Other common sites include the angle of the mandible and the region of the canine tooth.
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Indirect Transmission of Energy: Fractures can occur due to indirect forces transmitted through the mandible, which may lead to fractures of the condyle even if the impact is not directly on that area.
Patterns of Mandibular Fractures
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Fracture of the Condylar Neck:
- Description: The neck of the condyle is the most common site for mandibular fractures. This area is particularly vulnerable due to its anatomical structure and the forces applied during trauma.
- Clinical Significance: Fractures in this area can affect the function of the temporomandibular joint (TMJ) and may lead to complications such as malocclusion or limited jaw movement.
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Fracture of the Angle of the Mandible:
- Description: The angle of the mandible is the second most common site for fractures, typically occurring through the last molar tooth.
- Clinical Significance: Fractures in this region can impact the integrity of the mandible and may lead to displacement of the fractured segments. They can also affect the function of the muscles of mastication.
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Fracture in the Region of the Canine Tooth:
- Description: The canine region is another weak point in the mandible, where fractures can occur due to trauma.
- Clinical Significance: Fractures in this area may involve the alveolar process and can affect the stability of the canine tooth, leading to potential complications in dental alignment and occlusion.
Additional Classification Systems
Mandibular fractures can also be classified based on various criteria, including:
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Location:
- Symphyseal Fractures: Fractures occurring at the midline of the mandible.
- Parasymphyseal Fractures: Fractures located just lateral to the midline.
- Body Fractures: Fractures occurring along the body of the mandible.
- Angle Fractures: Fractures at the angle of the mandible.
- Condylar Fractures: Fractures involving the condylar process.
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Type of Fracture:
- Simple Fractures: Fractures that do not involve the surrounding soft tissues.
- Compound Fractures: Fractures that communicate with the oral cavity or skin, leading to potential infection.
- Comminuted Fractures: Fractures that result in multiple fragments of bone.
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Displacement:
- Non-displaced Fractures: Fractures where the bone fragments remain in alignment.
- Displaced Fractures: Fractures where the bone fragments are misaligned, requiring surgical intervention for realignment.
Antral Puncture and Intranasal Antrostomy
Antral puncture, also known as intranasal antrostomy, is a surgical procedure performed to access the maxillary sinus for diagnostic or therapeutic purposes. This procedure is commonly indicated in cases of chronic sinusitis, sinus infections, or to facilitate drainage of the maxillary sinus. Understanding the anatomical considerations and techniques for antral puncture is essential for successful outcomes.
Anatomical Considerations
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Maxillary Sinus Location:
- The maxillary sinus is one of the paranasal sinuses located within the maxilla (upper jaw) and is situated laterally to the nasal cavity.
- The floor of the maxillary sinus is approximately 1.25 cm below the floor of the nasal cavity, making it accessible through the nasal passages.
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Meatuses of the Nasal Cavity:
- The nasal cavity contains several meatuses, which are passageways
that allow for drainage of the sinuses:
- Middle Meatus: Located between the middle and inferior nasal conchae, it is the drainage pathway for the frontal, maxillary, and anterior ethmoid sinuses.
- Inferior Meatus: Located below the inferior nasal concha, it primarily drains the nasolacrimal duct.
- The nasal cavity contains several meatuses, which are passageways
that allow for drainage of the sinuses:
Technique for Antral Puncture
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Indications:
- Antral puncture is indicated for:
- Chronic maxillary sinusitis.
- Accumulation of pus or fluid in the maxillary sinus.
- Diagnostic aspiration for culture and sensitivity testing.
- Antral puncture is indicated for:
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Puncture Site:
- In Children: The puncture should be made through the middle meatus. This approach is preferred due to the anatomical differences in children, where the maxillary sinus is relatively smaller and more accessible through this route.
- In Adults: The puncture is typically performed through the inferior meatus. This site allows for better drainage and is often used for therapeutic interventions.
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Procedure:
- The patient is positioned comfortably, usually in a sitting or semi-reclined position.
- Local anesthesia is administered to minimize discomfort.
- A needle (often a 16-gauge or larger) is inserted through the chosen meatus into the maxillary sinus.
- Aspiration is performed to confirm entry into the sinus, and any fluid or pus can be drained.
- If necessary, saline may be irrigated into the sinus to help clear debris or infection.
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Post-Procedure Care:
- Patients may be monitored for any complications, such as bleeding or infection.
- Antibiotics may be prescribed if an infection is present or suspected.
- Follow-up appointments may be necessary to assess healing and sinus function.