Anatomical Subunit Repair of Unilateral Cleft Lip



Anatomical Subunit Repair of Unilateral Cleft Lip


David K. Chong

Kathryn V. Isaac





ANATOMY



  • During the 5th to 7th weeks of gestation, cleft lip occurs as a failure of complete union of the medial nasal process and the maxillary prominence.


  • Clefting occurs through the skin, muscle, and mucosa of the labial and nasal structures.


  • The cleft of the lip distorts and/or disrupts several important anatomic structures.



    • Muscles



      • Orbicularis oris (pars marginalis and pars peripheralis)


      • Pars alaris, depressor alae nasi


    • Upper lip



      • Cutaneous lip: philtral columns, central dimple, cutaneous roll


      • Red lip: Cupid’s bow, vermillion, mucosa


    • Nose



      • Nasal floor, alar base, nasal cartilages, septum, columella


PATHOGENESIS



  • The etiology of cleft lip is genetically complex and is due to multiple genetic and environmental risk factors.



    • Most cases are sporadic, but some are familial, X-linked, or autosomal dominant. Familial history of clefting is an important risk factor.


  • Cleft lip and cleft lip with cleft palate are considered variants of an entity that differ in severity.



    • The environmental risk factors associated with clefting include maternal smoking, infection, poor nutrition, teratogen exposure (alcohol, phenytoin, valproic acid, retinoic acid), and advanced paternal age.


PATIENT HISTORY AND PHYSICAL FINDINGS



  • Diagnosis of a cleft lip is made by prenatal ultrasonography, by MRI, or by physical examination at birth. Detailed assessment is made of the child’s breathing, feeding, growth, and development.


  • Assessment of growth and weight is key to identify and monitor feeding difficulty and use of feeding aids (Haberman/Pigeon teat).


  • The plastic surgeon should define the cleft lip type according to the anatomic structures involved, laterality, width of the cleft, and presence/absence of a cleft palate.


  • Also, the child should be assessed for associated anomalies suggestive of a syndrome—craniofacial dysmorphism, airway compromise, cardiac defects, ocular and auricular abnormalities, and musculoskeletal anomalies. A genetics referral is suggested if suspicious of a syndromic etiology.




SURGICAL MANAGEMENT



  • Cleft lip repair is ideally performed at age 6 months because the landmarks are larger and easier to identify.


  • The principles of the anatomical subunit repair enable the surgeon to formulate a plan for the predictable and successful closure of any type of cleft lip.1


  • The labial cleft closure is designed, measured, and determined prior to skin incision. The operation is the execution of a formulated plan. This eliminates the potential of compromising landmarks and removes the fear of underrotation, as well as lip height or length discrepancies.


  • With this repair, the most visible part of the scar lies along the anatomical subunits, and the labial elements are perfectly matched in length to create an optimal continuity of vermilion, cutaneous lip, and alar-labial junction.


  • Rotation of the labial elements is achieved by:



    • Skin triangle above the cutaneous roll


    • Muscle repair


    • Mucosal release



  • Risks of the procedure are scar deformity, nasolabial asymmetry and/or deformity, wound dehiscence, and infection.


  • The main objectives of the cleft lip repair are to (1) separate the nasal and oral cavities; (2) restore lip continuity and continence; (3) reconstruct a functional labial sphincter for facial expression, speech, and feeding; (4) and restore aesthetics of the labial and nasal subunits.


  • The main steps of the procedures are as follows:



    • Marking key landmarks and designing closure of labial elements based on pre-incision measurements


    • Medial lip element release of skin, muscle, and mucosa to adequately balance the Cupid’s bow, then composite elevation of lateral lip elements to insert into the created “jigsaw”


    • Restoration of muscle continuity


    • Closure of the mucosa


    • Closure of the nasal floor


    • Skin and vermilion closure


    • Nasal correction with suture techniques


  • In discussing this repair, the language used in Millard’s description of the rotation-advancement cleft lip repair will be used.2 The application of this language will help to clarify and describe this technique for surgeons who have adopted the Millard technique or modifications of it.


Preoperative Planning



  • If the child has a cleft lip and cleft palate, dentofacial orthopedics are utilized for aligning the cleft maxillary arches and improving the nasal deformity (lower lateral cartilage shape and position and septal cartilage alignment). The device is discontinued prior to the cleft lip repair.


Positioning



  • The patient is positioned supine with the neck neutral and head stabilized in a head ring.


  • The surgeon must have the ability to freely examine the face from all angles throughout the procedure to ensure that three-dimensional balance is achieved. Corneas are protected with transparent tape to use the plane and position of the eyes in the surgical field as an aid to assessing labial and nasal symmetry. The transparent tape should still allow the cheek to move freely.


  • Loupe magnification is helpful for accurate identification of anatomical landmarks, for precise tissue dissection, and for perfect approximation.


Approach



  • Successful application of this cleft lip repair is facilitated by highlighting conceptual differences between the rotationadvancement repair and anatomic subunit repair.


  • Important landmarks are marked out, never compromised, and incisions are made for closure that follows anatomical subunits.



    • Paradigm shift: Spend more time marking before any incisions are made and the surgeon is committed to the plan.


  • Calipers are used to measure incisions for perfect length match.



    • Paradigm shift: The artistic “eye” is supplemented by precise measurements.


  • Foundation of repair is in the muscle.



    • Paradigm shift: Extension of skin incision outside of the proposed philtrum to achieve rotation is not required.


  • Inferior triangle is placed above the cutaneous roll. This location restores the cutaneous roll without interruption and achieves any additional lip lengthening required for the skin.



    • Paradigm shift: Triangle is premeasured. Most measure 1 to 2 mm because the muscle repair and mucosal M flap both contribute to lip lengthening.

Feb 27, 2020 | Posted by in Pediatric plastic surgery | Comments Off on Anatomical Subunit Repair of Unilateral Cleft Lip

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