NEET MDS Lessons
Oral and Maxillofacial Surgery
Intraligamentary Injection and Supraperiosteal Technique
Intraligamentary Injection
- The intraligamentary injection technique is a simple and effective method for achieving localized anesthesia in dental procedures. It requires only a small volume of anesthetic solution and produces rapid onset of anesthesia.
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Technique:
- Needle Placement:
- The needle is inserted into the gingival sulcus, typically on the mesial surface of the tooth.
- The needle is then advanced along the root surface until resistance is encountered, indicating that the needle is positioned within the periodontal ligament.
- Anesthetic Delivery:
- Approximately 0.2 ml of anesthetic solution is deposited into the periodontal ligament space.
- For multirooted teeth, injections should be made both mesially and distally to ensure adequate anesthesia of all roots.
- Needle Placement:
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Considerations:
- Significant pressure is required to express the anesthetic solution into the periodontal ligament, which can be a factor to consider during administration.
- This technique is particularly useful for localized procedures where rapid anesthesia is desired.
Supraperiosteal Technique (Local Infiltration)
- The supraperiosteal injection technique is commonly used for achieving anesthesia in the maxillary arch, particularly for single-rooted teeth.
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Technique:
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Anesthetic Injection:
- For the first primary molar, the bone overlying the tooth is thin, allowing for effective anesthesia by injecting the anesthetic solution opposite the apices of the roots.
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Challenges with Multirooted Teeth:
- The thick zygomatic process can complicate the anesthetic delivery for the buccal roots of the second primary molar and first permanent molars.
- Due to the increased thickness of bone in this area, the supraperiosteal injection at the apices of the roots of the second primary molar may be less effective.
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Supplemental Injection:
- To enhance anesthesia, a supplemental injection should be administered superior to the maxillary tuberosity area to block the posterior superior alveolar nerve.
- This additional injection compensates for the bone thickness and the presence of the posterior middle superior alveolar nerve plexus, which can affect the efficacy of the initial injection.
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Transoral Lithotomy: Procedure for Submandibular Duct Stone Removal
Transoral lithotomy is a surgical technique used to remove stones (calculi) from the submandibular duct (Wharton's duct). This procedure is typically performed under local anesthesia and is effective for addressing sialolithiasis (the presence of stones in the salivary glands).
Procedure
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Preoperative Preparation:
- Radiographic Assessment: The exact location of the stone is determined using imaging studies, such as X-rays or ultrasound, to guide the surgical approach.
- Local Anesthesia: The procedure is performed under local anesthesia to minimize discomfort for the patient.
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Surgical Technique:
- Suture Placement: A suture is placed behind the stone to prevent it from moving backward during the procedure, facilitating easier access.
- Incision: An incision is made in the mucosa of the
floor of the mouth, parallel to the duct. Care is taken to avoid injury
to surrounding structures, including:
- Lingual Nerve: Responsible for sensory innervation to the tongue.
- Submandibular Gland: The gland itself should be preserved to maintain salivary function.
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Blunt Dissection:
- After making the incision, blunt dissection is performed to carefully displace the surrounding tissue and expose the duct.
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Identifying the Duct:
- The submandibular duct is located, and the segment of the duct that contains the stone is identified.
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Stone Removal:
- A longitudinal incision is made over the stone within the duct. The stone is then extracted using small forceps. Care is taken to ensure complete removal to prevent recurrence.
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Postoperative Considerations:
- After the stone is removed, the incision may be closed with sutures, and the area is monitored for any signs of complications.
Complications
- Bacterial Sialadenitis: If there is a secondary infection following the procedure, it can lead to bacterial sialadenitis, which is an inflammation of the salivary gland due to infection. Symptoms may include pain, swelling, and purulent discharge from the duct.
Vestibuloplasty
Vestibuloplasty is a surgical procedure aimed at deepening the vestibule of the oral cavity, which is the space between the gums and the inner lining of the lips and cheeks. This procedure is particularly important in prosthodontics and oral surgery, as it can enhance the retention and stability of dentures by increasing the available denture-bearing area.
Types of Vestibuloplasty
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Vestibuloplasty (Sulcoplasty or Sulcus Deepening Procedure):
- This procedure involves deepening the vestibule without the addition of bone. It is primarily focused on modifying the soft tissue to create a more favorable environment for denture placement.
- Indications:
- Patients with shallow vestibules that may compromise denture retention.
- Patients requiring improved aesthetics and function of their prostheses.
- Technique:
- The procedure typically involves the excision of the mucosa and submucosal tissue to create a deeper vestibule.
- The soft tissue is then repositioned to allow for a deeper sulcus, enhancing the area available for denture support.
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Labial Vestibular Procedure (Transpositional Flap Vestibuloplasty or Lip Switch Procedure):
- This specific type of vestibuloplasty involves the transposition of soft tissue from the inner aspect of the lip to a more favorable position on the alveolar bone.
- Indications:
- Patients with inadequate vestibular depth who require additional soft tissue coverage for denture support.
- Cases where the labial vestibule is shallow, affecting the retention of dentures.
- Technique:
- A flap is created from the inner lip, which is then mobilized and repositioned to cover the alveolar ridge.
- This procedure increases the denture-bearing area by utilizing the soft tissue from the lip, thereby enhancing the retention and stability of the denture.
- The flap is sutured into place, and the healing process allows for the integration of the new tissue position.
Benefits of Vestibuloplasty
- Increased Denture Retention: By deepening the vestibule and increasing the denture-bearing area, patients often experience improved retention and stability of their dentures.
- Enhanced Aesthetics: The procedure can improve the overall appearance of the oral cavity, contributing to better facial aesthetics.
- Improved Function: Patients may find it easier to eat and speak with well-retained dentures, leading to improved quality of life.
Considerations and Postoperative Care
- Healing Time: Patients should be informed about the expected healing time and the importance of following postoperative care instructions to ensure proper healing.
- Follow-Up: Regular follow-up appointments may be necessary to monitor healing and assess the need for any adjustments to the dentures.
- Potential Complications: As with any surgical procedure, there are risks involved, including infection, bleeding, and inadequate healing. Proper surgical technique and postoperative care can help mitigate these risks.
Management and Treatment of Le Fort Fractures
Le Fort fractures require careful assessment and management to restore facial anatomy, function, and aesthetics. The treatment approach may vary depending on the type and severity of the fracture.
Le Fort I Fracture
Initial Assessment:
- Airway Management: Ensure the airway is patent, especially if there is significant swelling or potential for airway compromise.
- Neurological Assessment: Evaluate for any signs of neurological injury.
Treatment:
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Non-Surgical Management:
- Observation: In cases of non-displaced fractures, close monitoring may be sufficient.
- Pain Management: Analgesics to manage pain.
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Surgical Management:
- Open Reduction and Internal Fixation (ORIF): Indicated for displaced fractures to restore occlusion and facial symmetry.
- Maxillomandibular Fixation (MMF): May be used temporarily to stabilize the fracture during healing.
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Postoperative Care:
- Follow-Up: Regular follow-up to monitor healing and occlusion.
- Oral Hygiene: Emphasize the importance of maintaining oral hygiene to prevent infection.
Le Fort II Fracture
Initial Assessment:
- Airway Management: Critical due to potential airway compromise.
- Neurological Assessment: Evaluate for any signs of neurological injury.
Treatment:
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Non-Surgical Management:
- Observation: For non-displaced fractures, close monitoring may be sufficient.
- Pain Management: Analgesics to manage pain.
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Surgical Management:
- Open Reduction and Internal Fixation (ORIF): Required for displaced fractures to restore occlusion and facial symmetry.
- Maxillomandibular Fixation (MMF): May be used to stabilize the fracture during healing.
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Postoperative Care:
- Follow-Up: Regular follow-up to monitor healing and occlusion.
- Oral Hygiene: Emphasize the importance of maintaining oral hygiene to prevent infection.
Le Fort III Fracture
Initial Assessment:
- Airway Management: Critical due to potential airway compromise and significant facial swelling.
- Neurological Assessment: Evaluate for any signs of neurological injury.
Treatment:
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Non-Surgical Management:
- Observation: In cases of non-displaced fractures, close monitoring may be sufficient.
- Pain Management: Analgesics to manage pain.
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Surgical Management:
- Open Reduction and Internal Fixation (ORIF): Essential for restoring facial anatomy and occlusion. This may involve complex reconstruction of the midface.
- Maxillomandibular Fixation (MMF): Often used to stabilize the fracture during healing.
- Craniofacial Reconstruction: In cases of severe displacement or associated injuries, additional reconstructive procedures may be necessary.
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Postoperative Care:
- Follow-Up: Regular follow-up to monitor healing, occlusion, and any complications.
- Oral Hygiene: Emphasize the importance of maintaining oral hygiene to prevent infection.
- Physical Therapy: May be necessary to restore function and mobility.
General Considerations for All Le Fort Fractures
- Antibiotic Prophylaxis: Consideration for prophylactic antibiotics to prevent infection, especially in open fractures.
- Nutritional Support: Ensure adequate nutrition, especially if oral intake is compromised.
- Psychological Support: Address any psychological impact of facial injuries, especially in pediatric patients.
Nasogastric Tube (Ryles Tube)
A nasogastric tube (NG tube), commonly referred to as a Ryles tube, is a medical device used for various purposes, primarily involving the stomach. It is a long, hollow tube made of polyvinyl chloride (PVC) with one blunt end and multiple openings along its length. The tube is designed to be inserted through the nostril, down the esophagus, and into the stomach.
Description and Insertion
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Structure: The NG tube has a blunt end that is inserted into the nostril, and it features multiple openings to allow for the passage of fluids and air. The open end of the tube is used for feeding or drainage.
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Insertion Technique:
- The tube is gently passed through one of the nostrils and advanced through the nasopharynx and into the esophagus.
- Care is taken to ensure that the tube follows the natural curvature of the nasal passages and esophagus.
- Once the tube is in place, its position must be confirmed before any feeds or medications are administered.
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Position Confirmation:
- To check the position of the tube, air is pushed into the tube using a syringe.
- The presence of air in the stomach is confirmed by auscultation with a stethoscope, listening for the characteristic "whoosh" sound of air entering the stomach.
- Only after confirming that the tube is correctly positioned in the stomach should feeding or medication administration begin.
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Securing the Tube: The tube is fixed to the nose using sticking plaster or adhesive tape to prevent displacement.
Uses of Nasogastric Tube
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Nutritional Support:
- Enteral Feeding: The primary use of a nasogastric
tube is to provide nutritional support to patients who are unable to
take oral feeds due to various reasons, such as:
- Neurological conditions (e.g., stroke, coma)
- Surgical procedures affecting the gastrointestinal tract
- Severe dysphagia (difficulty swallowing)
- Enteral Feeding: The primary use of a nasogastric
tube is to provide nutritional support to patients who are unable to
take oral feeds due to various reasons, such as:
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Gastric Lavage:
- Postoperative Care: NG tubes can be used for gastric lavage to flush out blood, fluids, or other contents from the stomach after surgery. This is particularly important in cases where there is a risk of aspiration or when the stomach needs to be emptied.
- Poisoning: In cases of poisoning or overdose, gastric lavage may be performed using an NG tube to remove toxic substances from the stomach. This procedure should be done promptly and under medical supervision.
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Decompression:
- Relieving Distension: The NG tube can also be used to decompress the stomach in cases of bowel obstruction or ileus, allowing for the removal of excess gas and fluid.
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Medication Administration:
- The tube can be used to administer medications directly into the stomach for patients who cannot take oral medications.
Considerations and Complications
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Patient Comfort: Insertion of the NG tube can be uncomfortable for patients, and proper technique should be used to minimize discomfort.
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Complications: Potential complications include:
- Nasal and esophageal irritation or injury
- Misplacement of the tube into the lungs, leading to aspiration
- Sinusitis or nasal ulceration with prolonged use
- Gastrointestinal complications, such as gastric erosion or ulceration
Hyperbaric Oxygen Therapy (HBOT)
Hyperbaric Oxygen Therapy (HBOT) is a medical treatment that involves the inhalation of 100% oxygen at pressures greater than atmospheric pressure, typically between 2 to 3 atmospheres (ATA). This therapy is used to enhance oxygen delivery to tissues, particularly in cases of ischemia, infection, and compromised healing. Below is a detailed overview of the advantages and mechanisms of HBOT, particularly in the context of surgical applications and tissue healing.
Mechanism of Action
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Increased Oxygen Availability:
- Under hyperbaric conditions, the solubility of oxygen in plasma increases significantly, allowing for greater oxygen delivery to tissues, even in areas with compromised blood flow.
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Enhanced Vascular Supply:
- HBOT promotes the formation of new blood vessels (neovascularization) and improves the overall vascular supply to tissues. This is particularly beneficial in areas that have been irradiated or are ischemic.
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Improved Oxygen Perfusion:
- The therapy enhances oxygen perfusion to ischemic areas, which is crucial for healing and recovery, especially in cases of infection or tissue damage.
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Bactericidal and Bacteriostatic Effects:
- Increased oxygen concentrations have a direct bactericidal effect on certain anaerobic bacteria and enhance the bacteriostatic action against aerobic bacteria. This can help in the management of infections, particularly in chronic wounds or osteomyelitis.
Advantages of Hyperbaric Oxygen Therapy
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Support for Soft Tissue Graft Healing:
- While HBOT may not fully recruit the vascular support necessary for sustaining bone graft healing, it is beneficial in supporting soft tissue graft healing. The increased oxygen supply helps minimize compartmentalization and promotes better integration of grafts.
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Revascularization of Irradiated Tissues:
- In patients with irradiated tissues, HBOT increases blood oxygen tension, enhancing the diffusion of oxygen into the tissues. This revascularization improves fibroblastic cellular density, which is essential for tissue repair and regeneration. It also limits the amount of non-viable tissue that may need to be surgically removed.
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Adjunctive Therapy in Surgical Procedures:
- HBOT is often used as an adjunctive therapy in surgical procedures involving compromised tissues, such as in cases of necrotizing fasciitis, diabetic foot ulcers, and chronic non-healing wounds. It can enhance the effectiveness of surgical interventions by improving tissue oxygenation and promoting healing.
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Reduction of Complications:
- By improving oxygenation and reducing the risk of infection, HBOT can help decrease postoperative complications, leading to better overall outcomes for patients undergoing surgery in compromised tissues.
Clinical Applications
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Osteoradionecrosis: HBOT is commonly used in the management of osteoradionecrosis, a condition that can occur in patients who have received radiation therapy for head and neck cancers. The therapy helps to revascularize the affected bone and improve healing.
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Chronic Wounds: It is effective in treating chronic wounds, particularly in diabetic patients, by enhancing oxygen delivery and promoting healing.
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Infection Management: HBOT is beneficial in managing infections, especially those caused by anaerobic bacteria, by increasing the local oxygen concentration and enhancing the immune response.
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Flap and Graft Survival: The therapy is used to improve the survival of flaps and grafts in reconstructive surgery by enhancing blood flow and oxygenation to the tissues.
Osteoradionecrosis
Osteoradionecrosis (ORN) is a condition that can occur following radiation therapy, particularly in the head and neck region, leading to the death of bone tissue due to compromised blood supply. The management of ORN is complex and requires a multidisciplinary approach. Below is a comprehensive overview of the treatment strategies for osteoradionecrosis.
1. Debridement
- Purpose: Surgical debridement involves the removal of necrotic and infected tissue to promote healing and prevent the spread of infection.
- Procedure: This may include the excision of necrotic bone and soft tissue, allowing for better access to healthy tissue.
2. Control of Infection
- Antibiotic Therapy: Broad-spectrum antibiotics are administered to control any acute infections present. However, it is important to note that antibiotics may not penetrate necrotic bone effectively due to poor circulation.
- Monitoring: Regular assessment of infection status is crucial to adjust antibiotic therapy as needed.
3. Hospitalization
- Indication: Patients with severe ORN or those requiring surgical intervention may need hospitalization for close monitoring and management.
4. Supportive Treatment
- Hydration: Fluid therapy is essential to maintain hydration and support overall health.
- Nutritional Support: A high-protein and vitamin-rich diet is recommended to promote healing and recovery.
5. Pain Management
- Analgesics: Both narcotic and non-narcotic analgesics are used to manage pain effectively.
- Regional Anesthesia: Techniques such as bupivacaine (Marcaine) injections, alcohol nerve blocks, nerve avulsion, and rhizotomy may be employed for more effective pain control.
6. Good Oral Hygiene
- Oral Rinses: Regular use of oral rinses, such as 1% sodium fluoride gel, 1% chlorhexidine gluconate, and plain water, helps prevent radiation-induced caries and manage xerostomia and mucositis. These rinses can enhance local immune responses and antimicrobial activity.
7. Frequent Irrigations of Wounds
- Purpose: Regular irrigation of the affected areas helps to keep the wound clean and free from debris, promoting healing.
8. Management of Exposed Dead Bone
- Removal of Loose Bone: Small pieces of necrotic bone that become loose can be removed easily to reduce the risk of infection and promote healing.
9. Sequestration Techniques
- Drilling: As recommended by Hahn and Corgill (1967), drilling multiple holes into vital bone can encourage the sequestration of necrotic bone, facilitating its removal.
10. Sequestrectomy
- Indication: Sequestrectomy involves the surgical removal of necrotic bone (sequestrum) and is preferably performed intraorally to minimize complications associated with skin and vascular damage from radiation.
11. Management of Pathological Fractures
- Fracture Treatment: Although pathological fractures are
not common, they may occur from minor injuries and do not heal readily. The
best treatment involves:
- Excision of necrotic ends of both bone fragments.
- Replacement with a large graft.
- Major soft tissue flap revascularization may be necessary to support reconstruction.
12. Bone Resection
- Indication: Bone resection is performed if there is persistent pain, infection, or pathological fracture. It is preferably done intraorally to avoid the risk of orocutaneous fistula in radiation-compromised skin.
13. Hyperbaric Oxygen (HBO) Therapy
- Adjunctive Treatment: HBO therapy can be a useful adjunct in the management of ORN. While it may not be sufficient alone to support bone graft healing, it can aid in soft tissue graft healing and minimize compartmentalization.