WP Chung_OT in Head and Neck Reconstructive Surgery_97819751

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Operative Techniques in Plastic Surgery: Head and Neck Reconstruction

■■ Use of EMLA in infants under 1 month of age (increased risk of methemoglobinemia) ■■ Lidocaine is pregnancy category B; however, lidocaine is excreted in breast milk ; therefore, caution is advised for use in breast-feeding mothers. ■■ Ocular exposure with EMLA should be avoided due to the presence of sodium hydroxide and the potential for alkaline injury. ■■ Caution is advised with concomitant use of EMLA and certain methemoglobinemia-inducing medications such as acetaminophen, anesthetics (prilocaine and benzocaine), anticonvulsants, antimalarials, nitrates, sulfonamides, and aniline dyes. ■■ Physical examination ■■ Ensure there is no skin breakdown or signs of infection or inflammatory lesions in areas where the agent will be applied/injected. ■■ Selection of agent ■■ Based on the anticipated procedure, the anesthetic is selected by taking into account the need for topical vs injectable modality, duration of the agent, and location of the procedure. ■■ The level of preprocedure patient anxiety should also be assessed and may determine the agent and application type used. SURGICAL MANAGEMENT ■■ Facial anesthesia is necessary for a variety of different cuta- neous procedures, including skin biopsies, excisions, Mohs micrographic surgery, surgical reconstruction, and laser and light-based therapies for facial resurfacing, scar revision, or lesion ablation. ■■ The decision to use an anesthetic and the selection of the agent is dependent partially on the type of procedure per- formed and the anticipated degree of discomfort. ■■ Facial nerve blocks are commonly implemented for abla- tive laser resurfacing of the entire face; however, there are reports of regional cutaneous nerve blocks for larger pig- mented or vascular facial lesions as well. ■■ Regional nerve blocks hold the advantage of minimizing significant tissue distortion, using less total volume of medi- cation, and less patient discomfort, but they are more chal- lenging to administer. ■■ Tumescent anesthesia is a form of local anesthesia using large volumes of highly dilute anesthetic delivered subcu- taneously, first described by Dr. Jeffrey Klein in the 1980s. ■■ It can be used alone or with various levels of sedation based on the intended procedure. ■■ While there is a wide range of usages for tumescent anes- thesia, face and neck uses generally include liposuction, face and neck lifts, dermabrasion, and full-face laser resurfacing. ■■ Lower volumes of fluid are infiltrated into the face (100– 150 mL per side) when compared with body infiltration, so the concentration of lidocaine may be higher for facial procedures. 3 Preoperative Planning ■■ Obtain an accurate patient weight to calculate the maxi- mum allotted anesthetic dose especially for procedures requiring larger volumes.

■■ Lidocaine toxicity is dose dependent, and it is critical to remain below the calculated maximum dose. ■■ It is also important to take into consideration individual patient characteristics as frail, elderly patients or those with underlying liver malfunction may require lower dosages. ■■ The maximum allotted dose of plain lidocaine for an adult patient is 4.5 mg/kg for whom the addition of epinephrine allows for up to 7 mg/kg 4 (see Table 1). ■■ The WiMP formula may also be used for ease of calculating maximum allotted dosages as long as the patient’s weight, maximum dosage, and percentage concentration of the agent are known. 5 ■■ V (mL) = (weight (kg) × 0.1 × maximum dose (mg/kg))/ percentage concentration Positioning ■■ Positioning is key to establishing both patient and provider comfort during the procedure. ■■ Ideally, the patient should be comfortably seated on the exam table with the table leaning back and the feet propped up to minimize a vasovagal reaction. ■■ The patient’s head should be firmly rested against the back of the table to allow for stabilization and minimize sudden movements when the needle is injected. ■■ It is best when injecting if the patient’s eyes are closed so they do not unintentionally pull away if they visualize the needle. ■■ For the surgeon, the table needs to be at an appropriate height, and the patient needs to be positioned closer to the surgeon’s side of the table to avoid excessive bending or reaching. ■■ The patient’s skin is held taut by either the surgeon’s non- dominant hand or an assistant. ■■ The surgeon’s nondominant hand may be used to stabilize the dominant hand during the injection. Alternatively, the surgeon may rest a few fingers of his or her dominant hand on other parts of the patient’s face to stabilize self. ■■ If an assistant is present, care must be taken to ensure the assistant is far enough from the anticipated injection tar- get to avoid accidental needlestick injury should a sudden movement occur. ■■ Additionally, the surgeon should be positioned so the needle is facing away from critical anatomic structures such as the globe of the eye to avoid an accidental puncture with unan- ticipated patient movement. Approach The topical anesthetic agents encompass a wide variety of noninvasive, painless products, which are commonly used prior to minimally invasive cosmetic procedures. ■■ Topical lidocaine and EMLA (eutectic mixture of local anesthetics) are the two most commonly used topical agents. ■■ Lidocaine is available in many formulations including cream, viscous solution, jelly, ointment, spray, and patches. ■■ Due to its unique liposomal delivery system to enhance penetration through the stratum corneum, lidocaine 4% cream (LMX-4, Ferndale Laboratories, Ferndale, MI) has the advantage of ease of application without occlusion, more rapid onset compared to EMLA (Astra Pharmaceuticals, Westborough, MA), and availability without a prescription. ■■ Topical agents ■■

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