Episode 08 — Incisions : extraoral incisions скачать в хорошем качестве

Episode 08 — Incisions : extraoral incisions

1️⃣ Coronal Approaches: Uni, Hemi, and Bicoronal These incisions provide superior access to the upper face, orbit, and zygomatic complex. *The Coronal Incision Principles* The design is dictated by two main factors: the patient's *hairline* and the *extent of inferior access* required. The incision is typically made through the skin, subcutaneous tissue, and galea, leading into the *subgaleal plane* overlying the pericranium. *. Uni/Hemicoronal Approach* *Location:* Begins in the preauricular area on the operative side and curves forward, ending just posterior to the midline hairline. This curve provides necessary relaxation for flap retraction. *Extension:* It can extend inferiorly, becoming a *preauricular incision* down to the ear lobule, allowing exposure of the zygomatic arch and the Temporomandibular Joint, or **TMJ**. *Indications:* Primarily for managing **unilateral midface fractures**, involving the frontozygomatic suture, orbital rim, or lateral orbital wall. *Precautions:* Avoid tearing the pericranium during dissection at the forehead where it is adherent to the frontalis muscle. Be mindful of the *superficial temporal artery* during the preauricular extension. * Bicoronal Approach* *Location:* This is a much broader incision, extending from one superior temporal line to the other, often called a "hair band incision." *Design Note for Males:* In anticipating future hairline recession, the incision line is often curved in a *zigzag manner* on the cranial side to better conceal the scar later. *Indications:* Essential for managing **bilateral midface fractures**, bilateral TMJ trauma, or conditions requiring extensive exposure of the nasoethmoidal area, superior orbital rim, and lateral orbital walls on both sides. *** 2️⃣ Transfacial Approaches to the Mandible These incisions grant direct access to the posterior body, angle, and ramus of the mandible. * Standard Submandibular and Risdon’s Approach* *Location:* The incision is strategically placed approximately *1.5 to 2 cm (or two finger breadths)* below the inferior border of the mandible. *Reasoning:* This precise placement is crucial to avoid injury to the **marginal mandibular branch of the facial nerve**. *Risdon's Modification:* This approach specifically *curls around the angle of the mandible* to provide superior access to the angle and ramus region. *Indications:* Extraoral access for mandibular angle and ramus fractures, cysts, tumors, or complex pathology not amenable to an intraoral approach. *Precautions:* Maintain the *1.5 to 2 cm safety margin* to protect the marginal mandibular nerve. Placing the incision within a natural *neck crease* minimizes the visibility of the final scar. Pre-op palpation of the *facial artery* is advised to avoid accidental injury. * Retromandibular Incision* *Location:* Begins about *0.5 cm below the ear lobule* and runs 3 to 3.5 cm inferiorly, placed just behind the posterior border of the mandibular ramus. *Indications:* Primarily used for surgeries involving the *condylar neck* and **ramus**. *Precautions:* Due to its proximity, extreme care must be taken to avoid injury to the *main trunk of the facial nerve* and the **retromandibular vein**. *** 3️⃣ Transfacial Approaches to the Mid-Face These complex incisions are used for extensive maxillary and nasal access, particularly in tumor and trauma surgery. * Lateral Rhinotomy* *Location:* Starts below the inner margin of the eyebrow, extends down along the nasomaxillary groove, and curves around the nasal ala to enter the nose. *Indications:* Provides direct access to the *nasal cavity* and the *maxillary antrum* for complex procedures like open rhinoplasties or tumor resections. * Weber-Ferguson Incision* *Description:* This is an extension of the Lateral Rhinotomy, used for maxillectomy procedures. The key difference from a standard rhinotomy is that the *upper lip is split* in the area of the philtrum to gain wider access. *Extensions:* *Lynch Extension:* Adds a cut from the medial canthus to the medial end of the upper eyebrow for greater access to the **medial orbital wall**. *Subciliary Extension:* Extends the incision laterally in the crease beneath the inferior eyelid (palpebra). *Indications:* Used for **partial, subtotal, or total maxillectomy**. *Critical Precaution:* When combining the infraorbital and lateral nasal parts of the incision, the angle formed at the junction must be **obtuse (rounded)**. A sharp or acute angle creates a critically narrow flap tip, which significantly increases the risk of **flap necrosis**.