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.

Management of Greenstick/Crack Fractures of the Mandible

Greenstick fractures (or crack fractures) are incomplete fractures that typically occur in children due to the flexibility of their bones. Fracture in mandible,  can often be managed conservatively, especially when there is no malocclusion (misalignment of the teeth).

Conservative Management

• No Fixation Required:
  • For greenstick fractures without malocclusion, surgical fixation is generally not necessary.
  • Closed Reduction: The fracture can be managed through closed reduction, which involves realigning the fractured bone without surgical exposure.
• Dietary Recommendations:
  • Patients are advised to consume soft foods and maintain adequate hydration with lots of fluids to facilitate healing and minimize discomfort during eating.

Surgical Management Options

In cases where surgical intervention is required, or for more complex fractures, the following methods can be employed:

1. Kirschner Wire (K-wire) Fixation:

   • Indications: K-wires can be used for both dentulous (having teeth) and edentulous (without teeth) mandibles.
   • Technique: K-wires are inserted through the bone fragments to stabilize the fracture. This method provides internal fixation and helps maintain alignment during the healing process.

2. Circumferential Wiring:

   • Indications: This technique is also applicable for both dentulous and edentulous mandibles.
   • Technique: Circumferential wiring involves wrapping wire around the mandible to stabilize the fracture. This method can provide additional support and is often used in conjunction with other fixation techniques.

3. External Pin Fixation:

   • Indications: Primarily used for edentulous mandibles.
   • Technique: External pin fixation involves placing pins into the bone that are connected to an external frame. This method allows for stabilization of the mandible while avoiding intraoral fixation, which can be beneficial in certain clinical scenarios.

Piezosurgery

Piezosurgery is an advanced surgical technique that utilizes ultrasonic vibrations to cut bone and other hard tissues with precision. This method has gained popularity in oral and maxillofacial surgery due to its ability to minimize trauma to surrounding soft tissues, enhance surgical accuracy, and improve patient outcomes. Below is a detailed overview of the principles, advantages, applications, and specific uses of piezosurgery in oral surgery.

Principles of Piezosurgery

• Ultrasonic Technology: Piezosurgery employs ultrasonic waves to create high-frequency vibrations in specially designed surgical tips. These vibrations allow for precise cutting of bone while preserving adjacent soft tissues.
• Selective Cutting: The ultrasonic frequency is tuned to selectively cut mineralized tissues (like bone) without affecting softer tissues (like nerves and blood vessels). This selectivity reduces the risk of complications and enhances healing.

Advantages of Piezosurgery

1. Strength and Durability of Tips:

   • Piezosurgery tips are made from high-quality materials that are strong and resistant to fracture. This durability allows for extended use without the need for frequent replacements, making them cost-effective in the long run.

2. Access to Difficult Areas:

   • The design of piezosurgery tips allows them to reach challenging anatomical areas that may be difficult to access with traditional surgical instruments. This is particularly beneficial in complex procedures involving the mandible and maxilla.

3. Minimized Trauma:

   • The ultrasonic cutting action produces less heat and vibration compared to traditional rotary instruments, which helps to preserve the integrity of surrounding soft tissues and reduces postoperative pain and swelling.

4. Enhanced Precision:

   • The ability to perform precise cuts allows for better control during surgical procedures, leading to improved outcomes and reduced complications.

5. Reduced Blood Loss:

   • The selective cutting action minimizes damage to blood vessels, resulting in less bleeding during surgery.

Applications in Oral Surgery

Piezosurgery has a variety of applications in oral and maxillofacial surgery, including:

1. Osteotomies:

   • LeFort I Osteotomy: Piezosurgery is particularly useful in performing pterygoid disjunction during LeFort I osteotomy. The ability to precisely cut bone in the pterygoid region allows for better access and alignment during maxillary repositioning.
   • Intraoral Vertical Ramus Osteotomy (IVRO): The lower border cut at the lateral surface of the ramus can be performed with piezosurgery, allowing for precise osteotomy while minimizing trauma to surrounding structures.
   • Inferior Alveolar Nerve Lateralization: Piezosurgery can be used to carefully lateralize the inferior alveolar nerve during procedures such as bone grafting or implant placement, reducing the risk of nerve injury.

2. Bone Grafting:

   • Piezosurgery is effective in harvesting bone grafts from donor sites, as it allows for precise cuts and minimal damage to surrounding tissues. This is particularly important in procedures requiring autogenous bone grafts.

3. Implant Placement:

   • The technique can be used to prepare the bone for dental implants, allowing for precise osteotomy and reducing the risk of complications associated with traditional drilling methods.

4. Sinus Lift Procedures:

   • Piezosurgery is beneficial in sinus lift procedures, where precise bone cutting is required to elevate the sinus membrane without damaging it.

5. Tumor Resection:

   • The precision of piezosurgery makes it suitable for resecting tumors in the jaw while preserving surrounding healthy tissue.

Characteristics of Middle-Third Facial Fractures

Middle-third facial fractures, often referred to as "midfacial fractures," involve the central portion of the face, including the nasal bones, maxilla, and zygomatic arch. These fractures can result from various types of trauma, such as motor vehicle accidents, falls, or physical assaults. The following points highlight the key features and clinical implications of middle-third facial fractures:

1. Oedema of the Middle Third of the Face

• Rapid Development: Oedema (swelling) in the middle third of the face develops quickly after the injury, leading to a characteristic "balloon" appearance. This swelling is due to the accumulation of fluid in the soft tissues of the face.

• Absence of Deep Cervical Fascia: The unique anatomical structure of the middle third of the face contributes to this swelling. The absence of deep cervical fascia in this region allows for the rapid spread of fluid, resulting in pronounced oedema.

• Clinical Presentation: In the early stages following injury, patients with middle-third fractures often present with similar facial appearances due to the characteristic swelling. This can make diagnosis based solely on visual inspection challenging.

2. Lengthening of the Face

• Displacement of the Middle Third: The downward and backward displacement of the middle third of the facial skeleton can lead to an increase in the overall length of the face. This displacement forces the mandible to open, which can result in a change in occlusion, particularly in the molar region.

• Gagging of Occlusion: The altered position of the mandible can lead to a malocclusion, where the upper and lower teeth do not align properly. This can cause discomfort and difficulty in chewing or speaking.

• Delayed Recognition of Lengthening: The true increase in facial length may not be fully appreciated until the initial oedema subsides. As the swelling decreases, the changes in facial structure become more apparent.

3. Nasal Obstruction

• Blood Clots in the Nares: Following a middle-third fracture, the nares (nostrils) may become obstructed by blood clots, leading to nasal congestion. This can significantly impact the patient's ability to breathe through the nose.

• Mouth Breathing: Due to the obstruction, patients are often forced to breathe through their mouths, which can lead to additional complications, such as dry mouth and increased risk of respiratory infections.

Unicystic Ameloblastoma

Unicystic ameloblastoma is a specific type of ameloblastoma characterized by a single cystic cavity that exhibits ameloblastomatous differentiation in its lining. This type of ameloblastoma is distinct from other forms due to its unique clinical, radiographic features, and behavior.

Characteristics of Unicystic Ameloblastoma

1. Definition:

   • Unicystic ameloblastoma is defined as a single cystic cavity that shows ameloblastomatous differentiation in the lining.

2. Clinical Features:

   • More than 90% of unicystic ameloblastomas are found in the posterior mandible.
   • They typically surround the crown of an unerupted mandibular third molar and may resemble a dentigerous cyst.

3. Radiographic Features:

   • Appears as a well-defined radiolucent lesion, often associated with the crown of an impacted tooth.

4. Histopathology:

   • There are three types of unicystic ameloblastomas:
     • Luminal: The cystic lining shows ameloblastomatous changes without infiltration into the wall.
     • Intraluminal: The tumor is located within the cystic cavity but does not infiltrate the wall.
     • Mural: The wall of the lesion is infiltrated by typical follicular or plexiform ameloblastoma. This type behaves similarly to conventional ameloblastoma and requires more aggressive treatment.

5. Recurrence Rate:

   • Unicystic ameloblastomas, particularly those without mural extension, have a low recurrence rate following conservative treatment.

Treatment of Ameloblastomas

1. Conventional (Follicular) Ameloblastoma:

   • Surgical Resection: Recommended with 1.0 to 1.5 cm margins and removal of one uninvolved anatomic barrier.
   • Enucleation and Curettage: If used, this method has a high recurrence rate (70-85%).

2. Unicystic Ameloblastoma (Without Mural Extension):

   • Conservative Treatment: Enucleation and curettage are typically successful due to the intraluminal location of the tumor.

3. Unicystic Ameloblastoma (With Mural Extension):

   • Aggressive Treatment: Managed similarly to conventional ameloblastomas due to the infiltrative nature of the mural component.

4. Intraosseous Solid and Multicystic Ameloblastomas:

   • Mandibular Excision: Block resection is performed, either with or without continuity defect, removing up to 1.5 cm of clinically normal bone around the margin.

5. Peripheral Ameloblastoma:

   • Simple Excision: These tumors are less aggressive and can be treated with simple excision, ensuring a rim of soft tissue tumor-free margins (1-1.5 cm).
   • If bone involvement is indicated by biopsy, block resection with continuity defect is preferred.

6. Recurrent Ameloblastoma:

   • Recurrences can occur 5-10 years after initial treatment and are best managed by resection with 1.5 cm margins.
   • Resection should be based on initial radiographs rather than those showing recurrence.

Distoangular Impaction

Distoangular impaction refers to the position of a tooth, typically a third molar (wisdom tooth), that is angled towards the back of the mouth and the distal aspect of the mandible. This type of impaction is often considered one of the most challenging to manage surgically due to its orientation and the anatomical considerations involved in its removal.

Characteristics of Distoangular Impaction

1. Pathway of Delivery:

   • The distoangular position of the tooth means that it is situated in a way that complicates its removal. The pathway for extraction often requires significant manipulation and access through the ascending ramus of the mandible.

2. Bone Removal:

   • A substantial amount of distal bone removal is necessary to access the tooth adequately. This may involve the use of surgical instruments to contour the bone and create sufficient space for extraction.

3. Crown Sectioning:

   • Once adequate bone removal has been achieved, the crown of the tooth is typically sectioned from the roots just above the cervical line. This step is crucial for improving visibility and access to the roots, which can be difficult to see and manipulate in their impacted position.

4. Removal of the Crown:

   • The entire crown is removed to facilitate better access to the roots. This step is essential for ensuring that the roots can be addressed without obstruction from the crown.

5. Root Management:

   • Divergent Roots: If the roots of the tooth are divergent (spreading apart), they may need to be further sectioned into two pieces. This allows for easier removal of each root individually, reducing the risk of fracture or complications during extraction.
   • Convergent Roots: If the roots are convergent (closer together), a straight elevator can often be used to remove the roots without the need for additional sectioning. The elevator is inserted between the roots to gently lift and dislodge them from the surrounding bone.

Surgical Technique Overview

1. Anesthesia: Local anesthesia is administered to ensure patient comfort during the procedure.

2. Incision and Flap Reflection: An incision is made in the mucosa, and a flap is reflected to expose the underlying bone and the impacted tooth.

3. Bone Removal: Using a surgical bur or chisel, the distal bone is carefully removed to create access to the tooth.

4. Crown Sectioning: The crown is sectioned from the roots using a surgical handpiece or bur, allowing for improved visibility.

5. Root Extraction:

   • For divergent roots, each root is sectioned and removed individually.
   • For convergent roots, a straight elevator is used to extract the roots.

6. Closure: After the tooth is removed, the surgical site is irrigated, and the flap is repositioned and sutured to promote healing.

Considerations and Complications

• Complications: Distoangular impactions can lead to complications such as nerve injury (especially to the inferior alveolar nerve), infection, and prolonged recovery time.
• Postoperative Care: Patients should be advised on postoperative care, including pain management, oral hygiene, and signs of complications such as swelling or infection.